diff --git a/regression/strings/cprover-string-hack.h b/regression/strings/cprover-string-hack.h
index 1ec17bca535..56bb66f7960 100644
--- a/regression/strings/cprover-string-hack.h
+++ b/regression/strings/cprover-string-hack.h
@@ -1,6 +1,5 @@
-typedef struct __CPROVER_string { char *s; } __CPROVER_string;
-//typedef struct __CPROVER_char { char c; } __CPROVER_char;
-typedef unsigned char __CPROVER_char;
+typedef struct __attribute__((__packed__)) __CPROVER_refined_string_type { int length; char content[]; } __CPROVER_refined_string_type;
+typedef __CPROVER_refined_string_type __CPROVER_string;
 
 /******************************************************************************
  * CPROVER string functions
@@ -54,19 +53,19 @@ typedef unsigned char __CPROVER_char;
 /******************************************************************************
  * don't use these directly
  ******************************************************************************/
-extern __CPROVER_char __CPROVER_uninterpreted_string_char_at_func(__CPROVER_string str, int pos);
+extern char __CPROVER_uninterpreted_string_char_at_func(__CPROVER_string str, int pos);
 extern __CPROVER_bool __CPROVER_uninterpreted_string_equal_func(__CPROVER_string str1, __CPROVER_string str2);
 extern __CPROVER_string __CPROVER_uninterpreted_string_literal_func(char * str);
-extern __CPROVER_char __CPROVER_uninterpreted_char_literal_func();
+extern char __CPROVER_uninterpreted_char_literal_func();
 extern __CPROVER_string __CPROVER_uninterpreted_string_concat_func(__CPROVER_string str1, __CPROVER_string str2);
 extern int __CPROVER_uninterpreted_string_length_func(__CPROVER_string str);
 extern __CPROVER_string __CPROVER_uninterpreted_string_substring_func(__CPROVER_string str, int i, int j);
 extern __CPROVER_bool __CPROVER_uninterpreted_string_is_prefix_func(__CPROVER_string pref, __CPROVER_string str);
 extern __CPROVER_bool __CPROVER_uninterpreted_string_is_suffix_func(__CPROVER_string suff, __CPROVER_string str);
 extern __CPROVER_bool __CPROVER_uninterpreted_string_contains_func(__CPROVER_string str1, __CPROVER_string str2);
-extern int __CPROVER_uninterpreted_string_index_of_func(__CPROVER_string str, __CPROVER_char c);
-extern int __CPROVER_uninterpreted_string_last_index_of_func(__CPROVER_string str, __CPROVER_char c);
-extern __CPROVER_string __CPROVER_uninterpreted_string_char_set_func(__CPROVER_string str, int pos, __CPROVER_char c);
+extern int __CPROVER_uninterpreted_string_index_of_func(__CPROVER_string str, char c);
+extern int __CPROVER_uninterpreted_string_last_index_of_func(__CPROVER_string str, char c);
+extern __CPROVER_string __CPROVER_uninterpreted_string_char_set_func(__CPROVER_string str, int pos, char c);
 extern __CPROVER_string __CPROVER_uninterpreted_string_copy_func(__CPROVER_string str);
 extern int __CPROVER_uninterpreted_string_parse_int_func(__CPROVER_string str);
 extern __CPROVER_string __CPROVER_uninterpreted_string_of_int_func(int i);
diff --git a/regression/strings/fixed_bugs/Makefile b/regression/strings/fixed_bugs/Makefile
new file mode 100644
index 00000000000..185be13bd7b
--- /dev/null
+++ b/regression/strings/fixed_bugs/Makefile
@@ -0,0 +1,9 @@
+
+test:
+	@../../test.pl -c ../../../../src/cbmc/cbmc
+
+testfuture:
+	@../../test.pl -c ../../../../src/cbmc/cbmc -CF
+
+testall:
+	@../../test.pl -c ../../../../src/cbmc/cbmc -CFTK
diff --git a/regression/strings/fixed_bugs/test-gen-095/test.class b/regression/strings/fixed_bugs/test-gen-095/test.class
new file mode 100644
index 00000000000..3895d218c3d
Binary files /dev/null and b/regression/strings/fixed_bugs/test-gen-095/test.class differ
diff --git a/regression/strings/fixed_bugs/test-gen-095/test.desc b/regression/strings/fixed_bugs/test-gen-095/test.desc
new file mode 100644
index 00000000000..2f1edf3ab8d
--- /dev/null
+++ b/regression/strings/fixed_bugs/test-gen-095/test.desc
@@ -0,0 +1,7 @@
+KNOWNBUG
+test.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/fixed_bugs/test-gen-095/test.java b/regression/strings/fixed_bugs/test-gen-095/test.java
new file mode 100644
index 00000000000..a6910527551
--- /dev/null
+++ b/regression/strings/fixed_bugs/test-gen-095/test.java
@@ -0,0 +1,10 @@
+public class test
+{
+   public static void main(String[] args)
+   {
+      StringBuilder sb = new StringBuilder(args[0]);
+      sb.append("Z");
+      String s = sb.toString();
+      assert(s.equals("fg"));
+   }
+}
diff --git a/regression/strings/java_case/test.desc b/regression/strings/java_case/test.desc
deleted file mode 100644
index 9f48288c694..00000000000
--- a/regression/strings/java_case/test.desc
+++ /dev/null
@@ -1,10 +0,0 @@
-FUTURE
-test_case.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_case.java line 11: SUCCESS$
-^\[assertion.2\] assertion at file test_case.java line 12: SUCCESS$
-^\[assertion.3\] assertion at file test_case.java line 13: SUCCESS$
-^\[assertion.4\] assertion at file test_case.java line 14: FAILURE$
---
diff --git a/regression/strings/java_case/test_case.class b/regression/strings/java_case/test_case.class
deleted file mode 100644
index 8579881de17..00000000000
Binary files a/regression/strings/java_case/test_case.class and /dev/null differ
diff --git a/regression/strings/java_case/test_case.java b/regression/strings/java_case/test_case.java
deleted file mode 100644
index ce3a51814c8..00000000000
--- a/regression/strings/java_case/test_case.java
+++ /dev/null
@@ -1,16 +0,0 @@
-public class test_case {
-
-    public static void main(String[] argv) {
-
-	String s = new String("AbcCdE");
-	String l = s.toLowerCase();
-	System.out.println(l);
-	
-	String u = s.toUpperCase();
-	System.out.println(u);
-	assert(l.equals("abccde"));
-	assert(u.equals("ABCCDE"));
-	assert(s.equalsIgnoreCase("ABccDe"));
-	assert(!l.equals("abccde") || !u.equals("ABCCDE"));
-    }
-}
diff --git a/regression/strings/java_char_array/test.desc b/regression/strings/java_char_array/test.desc
deleted file mode 100644
index 8282b808b84..00000000000
--- a/regression/strings/java_char_array/test.desc
+++ /dev/null
@@ -1,9 +0,0 @@
-FUTURE
-test_char_array.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_char_array.java line 11: SUCCESS$
-^\[assertion.2\] assertion at file test_char_array.java line 12: SUCCESS$
-^\[assertion.3\] assertion at file test_char_array.java line 13: FAILURE$
---
diff --git a/regression/strings/java_char_array/test_char_array.class b/regression/strings/java_char_array/test_char_array.class
deleted file mode 100644
index 836942da134..00000000000
Binary files a/regression/strings/java_char_array/test_char_array.class and /dev/null differ
diff --git a/regression/strings/java_char_array/test_char_array.java b/regression/strings/java_char_array/test_char_array.java
deleted file mode 100644
index 3cfd4000d3a..00000000000
--- a/regression/strings/java_char_array/test_char_array.java
+++ /dev/null
@@ -1,15 +0,0 @@
-public class test_char_array {
-
-    public static void main(String[] argv)
-    {
-        String s = "abc";
-        char [] str = s.toCharArray();
-        int[] test = new int[312];
-        char c = str[2];
-        String t = argv[0];
-        char d = t.charAt(0);
-        assert(str.length == 3);
-        assert(c == 'c');
-        assert(c == d || d < 'a' || d > 'z' );
-    }
-}
diff --git a/regression/strings/java_char_array_init/test.desc b/regression/strings/java_char_array_init/test.desc
deleted file mode 100644
index fe5ffae7238..00000000000
--- a/regression/strings/java_char_array_init/test.desc
+++ /dev/null
@@ -1,11 +0,0 @@
-FUTURE
-test_init.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_init.java line 16: SUCCESS$
-^\[assertion.2\] assertion at file test_init.java line 17: SUCCESS$
-^\[assertion.3\] assertion at file test_init.java line 18: SUCCESS$
-^\[assertion.4\] assertion at file test_init.java line 20: SUCCESS$
-^\[assertion.5\] assertion at file test_init.java line 21: FAILURE$
---
diff --git a/regression/strings/java_char_array_init/test_init.class b/regression/strings/java_char_array_init/test_init.class
deleted file mode 100644
index be3baee56bd..00000000000
Binary files a/regression/strings/java_char_array_init/test_init.class and /dev/null differ
diff --git a/regression/strings/java_char_array_init/test_init.java b/regression/strings/java_char_array_init/test_init.java
deleted file mode 100644
index 5f4e220844c..00000000000
--- a/regression/strings/java_char_array_init/test_init.java
+++ /dev/null
@@ -1,23 +0,0 @@
-public class test_init {
-
-    public static void main(String[] argv)
-    {
-	char [] str = new char[10];
-	str[0] = 'H';
-	str[1] = 'e';
-	str[2] = 'l';
-	str[3] = 'l';
-	str[4] = 'o';
-	String s = new String(str);
-	String t = new String(str,1,2);
-
-	System.out.println(s);
-	System.out.println(s.length());
-	assert(s.startsWith("Hello"));
-	assert(s.length() == 10);
-	assert(t.equals("el"));
-	String u = String.valueOf(str,3,2);
-	assert(u.equals("lo"));
-	assert(s.equals("Hello") || !t.equals("el") || !u.equals("lo"));
-    }
-}
diff --git a/regression/strings/java_char_at/test.desc b/regression/strings/java_char_at/test.desc
deleted file mode 100644
index 6f206a0f22f..00000000000
--- a/regression/strings/java_char_at/test.desc
+++ /dev/null
@@ -1,9 +0,0 @@
-FUTURE
-test_char_at.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_char_at.java line 11: SUCCESS$
-^\[assertion.2\] assertion at file test_char_at.java line 13: FAILURE$
-^\[assertion.3\] assertion at file test_char_at.java line 15: SUCCESS$
---
diff --git a/regression/strings/java_char_at/test_char_at.class b/regression/strings/java_char_at/test_char_at.class
deleted file mode 100644
index 7d1f07fad7d..00000000000
Binary files a/regression/strings/java_char_at/test_char_at.class and /dev/null differ
diff --git a/regression/strings/java_char_at/test_char_at.java b/regression/strings/java_char_at/test_char_at.java
deleted file mode 100644
index 337c6524099..00000000000
--- a/regression/strings/java_char_at/test_char_at.java
+++ /dev/null
@@ -1,17 +0,0 @@
-public class test_char_at {
-
-    public static void main(String[] argv) {
-	String s = new String("Hello World!");
-	char c = s.charAt(4);
-	StringBuilder sb = new StringBuilder(s);
-	sb.setCharAt(5,'-');
-	s = sb.toString();
-
-	if(argv.length==1)
-	    assert(c == 'o');
-	else if(argv.length==2)
-	    assert(c == 'p');
-	else
-	    assert(s.equals("Hello-World!"));
-    }
-}
diff --git a/regression/strings/java_code_point/test.desc b/regression/strings/java_code_point/test.desc
deleted file mode 100644
index 35ca0cd6f4b..00000000000
--- a/regression/strings/java_code_point/test.desc
+++ /dev/null
@@ -1,11 +0,0 @@
-FUTURE
-test_code_point.class
---string-refine
-^EXIT=0$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_code_point.java line 5: SUCCESS$
-^\[assertion.2\] assertion at file test_code_point.java line 6: SUCCESS$
-^\[assertion.3\] assertion at file test_code_point.java line 7: SUCCESS$
-^\[assertion.4\] assertion at file test_code_point.java line 8: SUCCESS$
-^\[assertion.5\] assertion at file test_code_point.java line 11: SUCCESS$
---
diff --git a/regression/strings/java_code_point/test_code_point.class b/regression/strings/java_code_point/test_code_point.class
deleted file mode 100644
index c257f0633ec..00000000000
Binary files a/regression/strings/java_code_point/test_code_point.class and /dev/null differ
diff --git a/regression/strings/java_code_point/test_code_point.java b/regression/strings/java_code_point/test_code_point.java
deleted file mode 100644
index c27a56f575c..00000000000
--- a/regression/strings/java_code_point/test_code_point.java
+++ /dev/null
@@ -1,13 +0,0 @@
-public class test_code_point {
-
-    public static void main(String[] argv) {
-	String s = "!𐤇𐤄𐤋𐤋𐤅"; 
-	assert(s.codePointAt(1) == 67847);
-	assert(s.codePointBefore(3) == 67847);
-	assert(s.codePointCount(1,5) >= 2);
-	assert(s.offsetByCodePoints(1,2) >= 3);
-	StringBuilder sb = new StringBuilder();
-	sb.appendCodePoint(0x10907);
-	assert(s.charAt(1) == sb.charAt(0));
-    }
-}
diff --git a/regression/strings/java_compare/test.desc b/regression/strings/java_compare/test.desc
deleted file mode 100644
index 517b208c3e4..00000000000
--- a/regression/strings/java_compare/test.desc
+++ /dev/null
@@ -1,10 +0,0 @@
-FUTURE
-test_compare.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_compare.java line 6: SUCCESS$
-^\[assertion.2\] assertion at file test_compare.java line 8: FAILURE$
-^\[assertion.3\] assertion at file test_compare.java line 11: SUCCESS$
-^\[assertion.4\] assertion at file test_compare.java line 12: FAILURE$
---
diff --git a/regression/strings/java_compare/test_compare.class b/regression/strings/java_compare/test_compare.class
deleted file mode 100644
index 5616013c523..00000000000
Binary files a/regression/strings/java_compare/test_compare.class and /dev/null differ
diff --git a/regression/strings/java_compare/test_compare.java b/regression/strings/java_compare/test_compare.java
deleted file mode 100644
index 8c1d4b71a0c..00000000000
--- a/regression/strings/java_compare/test_compare.java
+++ /dev/null
@@ -1,18 +0,0 @@
-public class test_compare {
-
-    public static void main(String[] argv) {
-	String s1 = "abc";
-	String s2 = "aac";
-	assert(s1.compareTo(s2) == 1);
-
-	assert(s2.compareTo(argv[0]) != -1);
-	
-	String s3 = "abc";
-	assert(s3.hashCode() == s1.hashCode());
-	assert(s3.hashCode() == s2.hashCode());
-			  
-	/*String x = s1.intern();
-	String y = s3.intern();
-	assert(x == y);*/
-    }
-}
diff --git a/regression/strings/java_concat/test.desc b/regression/strings/java_concat/test.desc
deleted file mode 100644
index 8ef2898e0d7..00000000000
--- a/regression/strings/java_concat/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_concat.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_concat.java line 9: SUCCESS$
-^\[assertion.2\] assertion at file test_concat.java line 10: FAILURE$
---
diff --git a/regression/strings/java_concat/test_concat.class b/regression/strings/java_concat/test_concat.class
deleted file mode 100644
index a6d4008aa26..00000000000
Binary files a/regression/strings/java_concat/test_concat.class and /dev/null differ
diff --git a/regression/strings/java_concat/test_concat.java b/regression/strings/java_concat/test_concat.java
deleted file mode 100644
index d714ea89538..00000000000
--- a/regression/strings/java_concat/test_concat.java
+++ /dev/null
@@ -1,12 +0,0 @@
-public class test_concat {
-
-    public static void main(String[] argv) {
-	String s = new String("pi");
-	int i = s.length();
-	String t = new String("ppo");
-	String u = s.concat(t);
-	char c = u.charAt(i);
-	assert(c == 'p');
-	assert(c == 'o');
-    }
-}
diff --git a/regression/strings/java_contains/test.desc b/regression/strings/java_contains/test.desc
deleted file mode 100644
index 4e7a3bd4f7d..00000000000
--- a/regression/strings/java_contains/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_contains.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_contains.java line 7: SUCCESS$
-^\[assertion.2\] assertion at file test_contains.java line 8: FAILURE$
---
diff --git a/regression/strings/java_contains/test_contains.class b/regression/strings/java_contains/test_contains.class
deleted file mode 100644
index 855ab828393..00000000000
Binary files a/regression/strings/java_contains/test_contains.class and /dev/null differ
diff --git a/regression/strings/java_contains/test_contains.java b/regression/strings/java_contains/test_contains.java
deleted file mode 100644
index fce2ee63047..00000000000
--- a/regression/strings/java_contains/test_contains.java
+++ /dev/null
@@ -1,10 +0,0 @@
-public class test_contains {
-
-    public static void main(String[] argv) {
-	String s = new String("Hello World!");
-	String u = "o W";
-	String t = "W o";
-	assert(s.contains(u));	
-	assert(s.contains(t));
-    }
-}
diff --git a/regression/strings/java_delete/test.desc b/regression/strings/java_delete/test.desc
deleted file mode 100644
index c6c608c0955..00000000000
--- a/regression/strings/java_delete/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_delete.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_delete.java line 11: SUCCESS$
-^\[assertion.2\] assertion at file test_delete.java line 12: FAILURE$
---
diff --git a/regression/strings/java_delete/test_delete.class b/regression/strings/java_delete/test_delete.class
deleted file mode 100644
index 6d30024f108..00000000000
Binary files a/regression/strings/java_delete/test_delete.class and /dev/null differ
diff --git a/regression/strings/java_delete/test_delete.java b/regression/strings/java_delete/test_delete.java
deleted file mode 100644
index c91b16c5b89..00000000000
--- a/regression/strings/java_delete/test_delete.java
+++ /dev/null
@@ -1,15 +0,0 @@
-public class test_delete {
-
-    public static void main(String[] argv) {
-	StringBuilder s = new StringBuilder();
-	s.append("Hello World!");
-	s.delete(4,6);
-	s.deleteCharAt(1);
-
-	String str = s.toString();
-	System.out.println(str);
-	assert(str.equals("HllWorld!"));
-	assert(!str.equals("HllWorld!"));
-
-    }
-}
diff --git a/regression/strings/java_easychair/easychair.java b/regression/strings/java_easychair/easychair.java
deleted file mode 100644
index 55ca2a31bb3..00000000000
--- a/regression/strings/java_easychair/easychair.java
+++ /dev/null
@@ -1,34 +0,0 @@
-public class easychair {
-
-    public static void main(String[] argv) {
-	if(argv.length > 1){
-	    String str = new String(argv[1]);
-	    if(str.length() < 40){
-
-		// containing "/" and containing "EasyChair"
-		int lastSlash = str.lastIndexOf('/');
-		if(lastSlash < 0) return ;
-		
-		String rest = str.substring(lastSlash + 1);
-		// warning: removed this because contains is not efficient at the moment
-		if(! rest.contains("EasyChair")) return ;
-		// (2) Check that str starts with "http://"
-		if(! str.startsWith("http://")) return ;
-		// (3) Take the string between "http://" and the last "/".
-		// if it starts with "www." strip the "www." off
-		String t = str.substring("http://".length(),lastSlash - "http://".length());
-		if(t.startsWith("www."))
-		    t = t.substring("www.".length());
-		
-		//
-		//(4) Check that after stripping we have either "live.com"
-		// or "google.com"
-		if(!t.equals("live.com") && !t.equals("google.com"))
-		    return ;
-		// s survived all checks
-		assert(false); //return true;
-	    }
-	}
-    }
-
-}
diff --git a/regression/strings/java_easychair/test.desc b/regression/strings/java_easychair/test.desc
deleted file mode 100644
index 8680af72c5a..00000000000
--- a/regression/strings/java_easychair/test.desc
+++ /dev/null
@@ -1,7 +0,0 @@
-FUTURE
-easychair.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file easychair.java line 29: FAILURE$
---
diff --git a/regression/strings/java_empty/test.desc b/regression/strings/java_empty/test.desc
deleted file mode 100644
index cab514b80b5..00000000000
--- a/regression/strings/java_empty/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_empty.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_empty.java line 4: SUCCESS$
-^\[assertion.2\] assertion at file test_empty.java line 5: FAILURE$
---
diff --git a/regression/strings/java_empty/test_empty.class b/regression/strings/java_empty/test_empty.class
deleted file mode 100644
index f0ced290ee3..00000000000
Binary files a/regression/strings/java_empty/test_empty.class and /dev/null differ
diff --git a/regression/strings/java_empty/test_empty.java b/regression/strings/java_empty/test_empty.java
deleted file mode 100644
index 2465fb16e41..00000000000
--- a/regression/strings/java_empty/test_empty.java
+++ /dev/null
@@ -1,7 +0,0 @@
-public class test_empty {
-    public static void main(String[] argv) {
-	String empty = "   ";
-	assert(empty.trim().isEmpty());
-	assert(empty.isEmpty());
-    }
-}
diff --git a/regression/strings/java_equal/test.desc b/regression/strings/java_equal/test.desc
deleted file mode 100644
index d66c30b26fe..00000000000
--- a/regression/strings/java_equal/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_equal.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_equal.java line 7: FAILURE$
-^\[assertion.2\] assertion at file test_equal.java line 8: SUCCESS$
---
diff --git a/regression/strings/java_equal/test_equal.java b/regression/strings/java_equal/test_equal.java
deleted file mode 100644
index 151162a106d..00000000000
--- a/regression/strings/java_equal/test_equal.java
+++ /dev/null
@@ -1,10 +0,0 @@
-public class test_equal {
-
-    public static void main(String[] argv) {
-	String s = new String("pi");
-	String t = new String("po");
-	String u = "po";
-	assert(s.equals(t));
-	assert(t.equals(u));
-    }
-}
diff --git a/regression/strings/java_float/test.desc b/regression/strings/java_float/test.desc
deleted file mode 100644
index 955f0358eab..00000000000
--- a/regression/strings/java_float/test.desc
+++ /dev/null
@@ -1,10 +0,0 @@
-FUTURE
-test_float.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_float.java line 14: SUCCESS$
-^\[assertion.2\] assertion at file test_float.java line 15: SUCCESS$
-^\[assertion.3\] assertion at file test_float.java line 16: SUCCESS$
-^\[assertion.4\] assertion at file test_float.java line 17: FAILURE$
---
diff --git a/regression/strings/java_float/test_float.java b/regression/strings/java_float/test_float.java
deleted file mode 100644
index e59c631d91e..00000000000
--- a/regression/strings/java_float/test_float.java
+++ /dev/null
@@ -1,20 +0,0 @@
-public class test_float {
-
-    public static void main(String[] arg) {
-	float inf = 100.0f / 0.0f;
-	float minus_inf = -100.0f / 0.0f;
-	float nan = 0.0f / 0.0f;
-	String inf_string = Float.toString(inf);
-	String mininf_string = Float.toString(minus_inf);
-	String nan_string = Float.toString(nan);
-	//String arg1 = arg[0];
-	System.out.println(nan_string);
-	System.out.println(inf_string);
-	System.out.println(mininf_string);
-	assert(nan_string.equals("NaN"));
-	assert(inf_string.equals("Infinity"));
-	assert(mininf_string.equals("-Infinity"));
-	assert(!nan_string.equals("NaN") || !inf_string.equals("Infinity")
-	       || !mininf_string.equals("-Infinity"));
-    }
-}
diff --git a/regression/strings/java_index_of/test.desc b/regression/strings/java_index_of/test.desc
deleted file mode 100644
index daa6c32493b..00000000000
--- a/regression/strings/java_index_of/test.desc
+++ /dev/null
@@ -1,16 +0,0 @@
-FUTURE
-test_index_of.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_index_of.java line 13: SUCCESS$
-^\[assertion.2\] assertion at file test_index_of.java line 14: FAILURE$
-^\[assertion.3\] assertion at file test_index_of.java line 17: SUCCESS$
-^\[assertion.4\] assertion at file test_index_of.java line 18: FAILURE$
-^\[assertion.5\] assertion at file test_index_of.java line 21: SUCCESS$
-^\[assertion.6\] assertion at file test_index_of.java line 22: FAILURE$
-^\[assertion.7\] assertion at file test_index_of.java line 25: SUCCESS$
-^\[assertion.8\] assertion at file test_index_of.java line 26: FAILURE$
-^\[assertion.9\] assertion at file test_index_of.java line 28: SUCCESS$
-^\[assertion.10\] assertion at file test_index_of.java line 29: SUCCESS$
---
diff --git a/regression/strings/java_index_of/test_index_of.class b/regression/strings/java_index_of/test_index_of.class
deleted file mode 100644
index 8b3b7525f1a..00000000000
Binary files a/regression/strings/java_index_of/test_index_of.class and /dev/null differ
diff --git a/regression/strings/java_index_of/test_index_of.java b/regression/strings/java_index_of/test_index_of.java
deleted file mode 100644
index bbe06d279ec..00000000000
--- a/regression/strings/java_index_of/test_index_of.java
+++ /dev/null
@@ -1,32 +0,0 @@
-public class test_index_of {
-
-    public static void main(String[] argv) {
-	String s = "Hello World!"; 
-	char c = 'o';
-	int i = s.indexOf(c);
-	int j = s.lastIndexOf('o');
-	int k = s.indexOf(c,5);
-	int l = s.lastIndexOf(c,5);
-	int m = s.indexOf("lo");
-	int n = s.lastIndexOf("lo");
-	if(argv.length == 1){
-	    assert(i == 4);
-	    assert(i != 4);
-	}
-	else if(argv.length == 2){
-	    assert(j == 7);	
-	    assert(j != 7);
-	}
-	else if(argv.length == 3){
-	    assert(k == 7);
-	    assert(k != 7);
-	}
-	else if(argv.length == 4){
-	    assert(l == 4);
-	    assert(l != 4);
-	} else {
-	    assert(m != 2);
-	    assert(n != 2);
-	}
-    }
-}
diff --git a/regression/strings/java_insert/test_insert.class b/regression/strings/java_insert/test_insert.class
deleted file mode 100644
index 5fa0f425061..00000000000
Binary files a/regression/strings/java_insert/test_insert.class and /dev/null differ
diff --git a/regression/strings/java_insert/test_insert.java b/regression/strings/java_insert/test_insert.java
deleted file mode 100644
index 6871a51716c..00000000000
--- a/regression/strings/java_insert/test_insert.java
+++ /dev/null
@@ -1,19 +0,0 @@
-public class test_insert {
-
-    public static void main(String[] argv) {
-	int i = 123;
-	long j = 123;
-	char c = '/';
-	boolean b = true;
-	StringBuilder sb = new StringBuilder("hello");
-	sb.insert(2,i);
-	sb.insert(2,c);
-	sb.insert(2,j);
-	sb.insert(2,b);
-	sb.insert(2,"abc");
-	String s = sb.toString();
-	System.out.println(s);
-	assert(s.equals("heabctrue123/123llo"));
-	assert(!s.equals("heabctrue123/123llo"));
-    }
-}
diff --git a/regression/strings/java_insert/test_insert1.class b/regression/strings/java_insert/test_insert1.class
deleted file mode 100644
index 80091936cea..00000000000
Binary files a/regression/strings/java_insert/test_insert1.class and /dev/null differ
diff --git a/regression/strings/java_insert/test_insert1.java b/regression/strings/java_insert/test_insert1.java
deleted file mode 100644
index 54e754302c5..00000000000
--- a/regression/strings/java_insert/test_insert1.java
+++ /dev/null
@@ -1,23 +0,0 @@
-public class test_insert1 {
-
-    public static void main(String[] argv) {
-	int i = 123;
-	long j = 123;
-	char c = '/';
-	boolean b = true;
-	StringBuilder sb = new StringBuilder("hello");
-	sb.insert(2,i);
-
-	/*
-	sb.insert(2,c);
-	sb.insert(2,j);
-	sb.insert(2,b);
-	sb.insert(2,"abc");
-	*/
-	String s = sb.toString();
-	System.out.println(s);
-	assert(s.equals("he123llo"));
-	//assert(s.equals("heabctrue123/123llo"));
-	//assert(!s.equals("heabctrue123/123llo"));
-    }
-}
diff --git a/regression/strings/java_int/test.desc b/regression/strings/java_int/test.desc
deleted file mode 100644
index ae60dd78af0..00000000000
--- a/regression/strings/java_int/test.desc
+++ /dev/null
@@ -1,13 +0,0 @@
-FUTURE
-test_int.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_int.java line 8: SUCCESS$
-^\[assertion.2\] assertion at file test_int.java line 9: SUCCESS$
-^\[assertion.3\] assertion at file test_int.java line 12: SUCCESS$
-^\[assertion.4\] assertion at file test_int.java line 15: SUCCESS$
-^\[assertion.5\] assertion at file test_int.java line 18: SUCCESS$
-^\[assertion.6\] assertion at file test_int.java line 21: SUCCESS$
-^\[assertion.7\] assertion at file test_int.java line 23: FAILURE$
---
diff --git a/regression/strings/java_int/test_int.class b/regression/strings/java_int/test_int.class
deleted file mode 100644
index 643d7eca09c..00000000000
Binary files a/regression/strings/java_int/test_int.class and /dev/null differ
diff --git a/regression/strings/java_int/test_int.java b/regression/strings/java_int/test_int.java
deleted file mode 100644
index 620ae638dce..00000000000
--- a/regression/strings/java_int/test_int.java
+++ /dev/null
@@ -1,25 +0,0 @@
-public class test_int {
-
-    public static void main(String[] argv) {
-	String s = Integer.toString(2345);
-	char c = s.charAt(1);
-	char d = s.charAt(2);
-	char e = s.charAt(3);
-	assert(c == '3');
-	assert(d == '4');
-
-	int i = Integer.parseInt("1234");
-	assert(i == 1234);
-
-	String t = Integer.toString(-2345);
-	assert(t.charAt(0) == '-');
-	
-	int j = Integer.parseInt("-4231");
-	assert(j == -4231);
-
-	String u = Integer.toHexString(43981);
-	assert(u.equals("abcd"));
-
-	assert(e == '2' || i < 1234 || t.charAt(0) != '-' || j != -4231 || !u.equals("abcd"));
-    }
-}
diff --git a/regression/strings/java_prefix/test.desc b/regression/strings/java_prefix/test.desc
deleted file mode 100644
index 175f934ca1d..00000000000
--- a/regression/strings/java_prefix/test.desc
+++ /dev/null
@@ -1,10 +0,0 @@
-FUTURE
-test_prefix.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_prefix.java line 14: SUCCESS$
-^\[assertion.2\] assertion at file test_prefix.java line 16: FAILURE$
-^\[assertion.3\] assertion at file test_prefix.java line 18: SUCCESS$
-^\[assertion.4\] assertion at file test_prefix.java line 20: FAILURE$
---
diff --git a/regression/strings/java_prefix/test_prefix.class b/regression/strings/java_prefix/test_prefix.class
deleted file mode 100644
index 6f5f4025932..00000000000
Binary files a/regression/strings/java_prefix/test_prefix.class and /dev/null differ
diff --git a/regression/strings/java_prefix/test_prefix.java b/regression/strings/java_prefix/test_prefix.java
deleted file mode 100644
index c9b5fa72fcf..00000000000
--- a/regression/strings/java_prefix/test_prefix.java
+++ /dev/null
@@ -1,23 +0,0 @@
-public class test_prefix {
-
-    public static void main(String[] argv) {
-	String s = new String("Hello World!");
-	//String t = new String("Hello");
-	//String u = new String("Wello");
-	String u = "Wello";
-	boolean b = s.startsWith("Hello");
-	//boolean c = s.startsWith("Wello");
-	//boolean b = s.startsWith(t);
-	boolean c = s.startsWith(u);
-	boolean d = s.startsWith("lo",3);
-	if(argv.length == 1){
-	    assert(b);	
-	} else if(argv.length == 2){
-	    assert(c);
-	} else if(argv.length == 3){
-	    assert(d);
-	} else if(argv.length == 4){	
-	    assert(!d);
-	}
-    }
-}
diff --git a/regression/strings/java_replace/test.desc b/regression/strings/java_replace/test.desc
deleted file mode 100644
index 1e89ebe37b4..00000000000
--- a/regression/strings/java_replace/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_replace.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_replace.java line 6: SUCCESS$
-^\[assertion.2\] assertion at file test_replace.java line 8: FAILURE$
---
diff --git a/regression/strings/java_replace/test_replace.class b/regression/strings/java_replace/test_replace.class
deleted file mode 100644
index c795826dc15..00000000000
Binary files a/regression/strings/java_replace/test_replace.class and /dev/null differ
diff --git a/regression/strings/java_replace/test_replace.java b/regression/strings/java_replace/test_replace.java
deleted file mode 100644
index 342bf9afddc..00000000000
--- a/regression/strings/java_replace/test_replace.java
+++ /dev/null
@@ -1,10 +0,0 @@
-public class test_replace {
-
-    public static void main(String[] argv) {
-	String s = new String("Hello World!");
-	String t = s.replace('o','u');
-	assert(t.equals("Hellu Wurld!"));
-	System.out.println(t);
-	assert(!t.equals("Hellu Wurld!"));
-    }
-}
diff --git a/regression/strings/java_set_length/test.desc b/regression/strings/java_set_length/test.desc
deleted file mode 100644
index 43f82a648fd..00000000000
--- a/regression/strings/java_set_length/test.desc
+++ /dev/null
@@ -1,9 +0,0 @@
-FUTURE
-test_set_length.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_set_length.java line 8: SUCCESS$
-^\[assertion.2\] assertion at file test_set_length.java line 9: SUCCESS$
-^\[assertion.3\] assertion at file test_set_length.java line 10: FAILURE$
---
diff --git a/regression/strings/java_set_length/test_set_length.class b/regression/strings/java_set_length/test_set_length.class
deleted file mode 100644
index 8836640967a..00000000000
Binary files a/regression/strings/java_set_length/test_set_length.class and /dev/null differ
diff --git a/regression/strings/java_set_length/test_set_length.java b/regression/strings/java_set_length/test_set_length.java
deleted file mode 100644
index 97b20f2332d..00000000000
--- a/regression/strings/java_set_length/test_set_length.java
+++ /dev/null
@@ -1,12 +0,0 @@
-public class test_set_length {
-
-    public static void main(String[] argv) {
-
-	StringBuilder s = new StringBuilder("abc");
-	s.setLength(10);
-	String t = s.toString();
-	assert(t.startsWith("abc"));
-	assert(t.length() == 10);
-	assert(t.length() == 3);
-    }
-}
diff --git a/regression/strings/java_string_builder/test.desc b/regression/strings/java_string_builder/test.desc
deleted file mode 100644
index 9712205b104..00000000000
--- a/regression/strings/java_string_builder/test.desc
+++ /dev/null
@@ -1,9 +0,0 @@
-FUTURE
-test_string_builder.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_string_builder.java line 11: SUCCESS$
-^\[assertion.2\] assertion at file test_string_builder.java line 12: SUCCESS$
-^\[assertion.3\] assertion at file test_string_builder.java line 13: FAILURE$
---
diff --git a/regression/strings/java_string_builder/test_string_builder.class b/regression/strings/java_string_builder/test_string_builder.class
deleted file mode 100644
index 7a61d1f02be..00000000000
Binary files a/regression/strings/java_string_builder/test_string_builder.class and /dev/null differ
diff --git a/regression/strings/java_string_builder/test_string_builder.java b/regression/strings/java_string_builder/test_string_builder.java
deleted file mode 100644
index 1d76b34e9f8..00000000000
--- a/regression/strings/java_string_builder/test_string_builder.java
+++ /dev/null
@@ -1,16 +0,0 @@
-public class test_string_builder {
-    public static void main(String[] argv) {
-	if(argv.length > 2) {
-	    StringBuilder tmp = new StringBuilder(); 
-	    tmp.append("prefix ");
-	    tmp.append(argv[1]);
-	    tmp.append(" middle ").append(argv[2]).append(" end");
-	    //StringBuilder tmp1 = tmp.append(argv[2]);
-	    //tmp1.append(" end");
-	    String r = tmp.toString();
-	    assert(r.startsWith("pref"));	    
-	    assert(r.endsWith("end"));
-	    assert(r.startsWith("pr3f"));
-	}
-    }
-}
diff --git a/regression/strings/java_string_builder_insert/test.desc b/regression/strings/java_string_builder_insert/test.desc
deleted file mode 100644
index 2655f846da1..00000000000
--- a/regression/strings/java_string_builder_insert/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_insert.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_insert.java line 17: SUCCESS$
-^\[assertion.2\] assertion at file test_insert.java line 18: FAILURE$
---
diff --git a/regression/strings/java_string_builder_insert/test_insert.class b/regression/strings/java_string_builder_insert/test_insert.class
deleted file mode 100644
index 69a32d7f93f..00000000000
Binary files a/regression/strings/java_string_builder_insert/test_insert.class and /dev/null differ
diff --git a/regression/strings/java_string_builder_insert/test_insert.java b/regression/strings/java_string_builder_insert/test_insert.java
deleted file mode 100644
index 1fac897c5ed..00000000000
--- a/regression/strings/java_string_builder_insert/test_insert.java
+++ /dev/null
@@ -1,20 +0,0 @@
-public class test_insert {
-
-    public static void main(String[] argv)
-    {
-	char [] str = new char[5];
-	str[0] = 'H';
-	str[1] = 'e';
-	str[2] = 'l';
-	str[3] = 'l';
-	str[4] = 'o';
-
-
-	StringBuilder sb = new StringBuilder(" world");
-	sb.insert(0,str);
-	String s = sb.toString();
-	System.out.println(s);
-	assert(s.equals("Hello world"));
-	assert(!s.equals("Hello world"));
-    }
-}
diff --git a/regression/strings/java_string_builder_length/test.desc b/regression/strings/java_string_builder_length/test.desc
deleted file mode 100644
index c4720992571..00000000000
--- a/regression/strings/java_string_builder_length/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_sb_length.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-\[assertion.1\] assertion at file test_sb_length.java line 6: SUCCESS$
-\[assertion.2\] assertion at file test_sb_length.java line 8: FAILURE$
---
diff --git a/regression/strings/java_string_builder_length/test_sb_length.class b/regression/strings/java_string_builder_length/test_sb_length.class
deleted file mode 100644
index 586e8f71935..00000000000
Binary files a/regression/strings/java_string_builder_length/test_sb_length.class and /dev/null differ
diff --git a/regression/strings/java_string_builder_length/test_sb_length.java b/regression/strings/java_string_builder_length/test_sb_length.java
deleted file mode 100644
index 652b72cdc90..00000000000
--- a/regression/strings/java_string_builder_length/test_sb_length.java
+++ /dev/null
@@ -1,11 +0,0 @@
-public class test_sb_length {
-    public static void main(String[] argv) {
-	StringBuilder tmp = new StringBuilder("prefix"); 
-	//tmp.append("prefix");
-	tmp.append("end");
-	assert(tmp.length() == 9);	    
-	if(argv.length > 1) {
-	    assert(tmp.length() == 12);	    
-	}
-    }
-}
diff --git a/regression/strings/java_strlen/test.desc b/regression/strings/java_strlen/test.desc
deleted file mode 100644
index b98e6f76f0a..00000000000
--- a/regression/strings/java_strlen/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_length.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_length.java line 10: SUCCESS$
-^\[assertion.2\] assertion at file test_length.java line 11: FAILURE$
---
diff --git a/regression/strings/java_strlen/test_length.class b/regression/strings/java_strlen/test_length.class
deleted file mode 100644
index 7f1c10c02ca..00000000000
Binary files a/regression/strings/java_strlen/test_length.class and /dev/null differ
diff --git a/regression/strings/java_strlen/test_length.java b/regression/strings/java_strlen/test_length.java
deleted file mode 100644
index 9410315db38..00000000000
--- a/regression/strings/java_strlen/test_length.java
+++ /dev/null
@@ -1,14 +0,0 @@
-public class test_length {
-
-    public static void main(String[] argv) {
-	String s = new String("hello");
-	if(argv.length > 1) {
-	    String t = argv[1];
-	    int i = t.length();
-	    String u = t.concat(s);
-	    char c = u.charAt(i);
-	    assert(c == 'h');
-	    assert(c == 'o');
-	}
-    }
-}
diff --git a/regression/strings/java_substring/test.desc b/regression/strings/java_substring/test.desc
deleted file mode 100644
index bd54a8204fe..00000000000
--- a/regression/strings/java_substring/test.desc
+++ /dev/null
@@ -1,10 +0,0 @@
-FUTURE
-test_substring.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_substring.java line 12: SUCCESS$
-^\[assertion.2\] assertion at file test_substring.java line 13: FAILURE$
-^\[assertion.3\] assertion at file test_substring.java line 20: SUCCESS$
-^\[assertion.4\] assertion at file test_substring.java line 21: FAILURE$
---
diff --git a/regression/strings/java_substring/test_substring.class b/regression/strings/java_substring/test_substring.class
deleted file mode 100644
index e6532aca43e..00000000000
Binary files a/regression/strings/java_substring/test_substring.class and /dev/null differ
diff --git a/regression/strings/java_substring/test_substring.java b/regression/strings/java_substring/test_substring.java
deleted file mode 100644
index 8a2ac883cca..00000000000
--- a/regression/strings/java_substring/test_substring.java
+++ /dev/null
@@ -1,27 +0,0 @@
-public class test_substring {
-
-    public static void main(String[] argv) {
-	if(argv.length > 1) {
-	    String t = argv[1];
-
-	    if(t.length() == 6) {
-		String u = t.substring(2,4);
-		char c = u.charAt(1);
-		char d = t.charAt(3);
-		char e = t.charAt(4);
-		assert(c == d);
-		assert(c == e);
-	    }
-	    else if(t.length() == 5){
-		CharSequence u = t.subSequence(2,4);
-		char c = u.charAt(1);
-		char d = t.charAt(3);
-		char e = t.charAt(4);
-		assert(c == d);
-		assert(c == e);
-	    }
-		
-
-	}
-    }
-}
diff --git a/regression/strings/java_suffix/test.desc b/regression/strings/java_suffix/test.desc
deleted file mode 100644
index 2740e87d6e4..00000000000
--- a/regression/strings/java_suffix/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_suffix.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_suffix.java line 12: SUCCESS$
-^\[assertion.2\] assertion at file test_suffix.java line 13: FAILURE$
---
diff --git a/regression/strings/java_suffix/test_suffix.class b/regression/strings/java_suffix/test_suffix.class
deleted file mode 100644
index 557acd02653..00000000000
Binary files a/regression/strings/java_suffix/test_suffix.class and /dev/null differ
diff --git a/regression/strings/java_suffix/test_suffix.java b/regression/strings/java_suffix/test_suffix.java
deleted file mode 100644
index f61b0b8ba36..00000000000
--- a/regression/strings/java_suffix/test_suffix.java
+++ /dev/null
@@ -1,15 +0,0 @@
-public class test_suffix {
-
-    public static void main(String[] argv) {
-	String s = new String("Hello World!");
-	//String t = new String("Hello");
-	//String u = new String("Wello");
-	String u = "Wello!";
-	boolean b = s.endsWith("World!");
-	//boolean c = s.startsWith("Wello");
-	//boolean b = s.startsWith(t);
-	boolean c = s.startsWith(u);
-	assert(b);	
-	assert(c);
-    }
-}
diff --git a/regression/strings/java_trim/test.desc b/regression/strings/java_trim/test.desc
deleted file mode 100644
index 7c0f1a87978..00000000000
--- a/regression/strings/java_trim/test.desc
+++ /dev/null
@@ -1,8 +0,0 @@
-FUTURE
-test_trim.class
---string-refine
-^EXIT=10$
-^SIGNAL=0$
-^\[assertion.1\] assertion at file test_trim.java line 5: SUCCESS$
-^\[assertion.2\] assertion at file test_trim.java line 6: FAILURE$
---
diff --git a/regression/strings/java_trim/test_trim.class b/regression/strings/java_trim/test_trim.class
deleted file mode 100644
index 8e6a923dcbc..00000000000
Binary files a/regression/strings/java_trim/test_trim.class and /dev/null differ
diff --git a/regression/strings/java_trim/test_trim.java b/regression/strings/java_trim/test_trim.java
deleted file mode 100644
index 8d8d41cb29a..00000000000
--- a/regression/strings/java_trim/test_trim.java
+++ /dev/null
@@ -1,8 +0,0 @@
-public class test_trim {
-    public static void main(String[] argv) {
-	String t = "  a b c  ";
-	String x = t.trim();
-	assert(x.equals("a b c"));
-	assert(x.equals("abc "));
-    }
-}
diff --git a/regression/strings/performance_tests/Makefile b/regression/strings/performance_tests/Makefile
new file mode 100644
index 00000000000..185be13bd7b
--- /dev/null
+++ b/regression/strings/performance_tests/Makefile
@@ -0,0 +1,9 @@
+
+test:
+	@../../test.pl -c ../../../../src/cbmc/cbmc
+
+testfuture:
+	@../../test.pl -c ../../../../src/cbmc/cbmc -CF
+
+testall:
+	@../../test.pl -c ../../../../src/cbmc/cbmc -CFTK
diff --git a/regression/strings/performance_tests/java_append_char/test.desc b/regression/strings/performance_tests/java_append_char/test.desc
new file mode 100644
index 00000000000..98e40b87b87
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_char.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 15.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_append_char/test_append_char.class b/regression/strings/performance_tests/java_append_char/test_append_char.class
new file mode 100644
index 00000000000..c0b1491423b
Binary files /dev/null and b/regression/strings/performance_tests/java_append_char/test_append_char.class differ
diff --git a/regression/strings/performance_tests/java_append_char/test_append_char.java b/regression/strings/performance_tests/java_append_char/test_append_char.java
new file mode 100644
index 00000000000..90e9ab089a2
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_char/test_append_char.java
@@ -0,0 +1,17 @@
+public class test_append_char
+{
+   public static void main(/*String[] args*/)
+   {
+      char[] diff = {'d', 'i', 'f', 'f'};
+      char[] blue = {'b', 'l', 'u', 'e'};
+
+      StringBuilder buffer = new StringBuilder();
+
+      buffer.append(diff)
+            .append(blue);
+
+      String tmp=buffer.toString();
+      System.out.println(tmp);
+      assert(!tmp.equals("diffblue"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_append_int/test.desc b/regression/strings/performance_tests/java_append_int/test.desc
new file mode 100644
index 00000000000..32659f65d7b
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_int/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_int.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_append_int/test_append_int.class b/regression/strings/performance_tests/java_append_int/test_append_int.class
new file mode 100644
index 00000000000..d9ee5046e7d
Binary files /dev/null and b/regression/strings/performance_tests/java_append_int/test_append_int.class differ
diff --git a/regression/strings/performance_tests/java_append_int/test_append_int.java b/regression/strings/performance_tests/java_append_int/test_append_int.java
new file mode 100644
index 00000000000..cf550211ad7
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_int/test_append_int.java
@@ -0,0 +1,11 @@
+public class test_append_int
+{
+   public static void main(/*String[] args*/)
+   {
+      StringBuilder diffblue = new StringBuilder();
+      diffblue.append("d");
+      diffblue.append(4);
+      String s = diffblue.toString();
+      assert(!s.equals("d4"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_append_object/test.desc b/regression/strings/performance_tests/java_append_object/test.desc
new file mode 100644
index 00000000000..cdfe4e20ecd
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_object/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_object.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 15.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_append_object/test_append_object.class b/regression/strings/performance_tests/java_append_object/test_append_object.class
new file mode 100644
index 00000000000..fbfec51a3f5
Binary files /dev/null and b/regression/strings/performance_tests/java_append_object/test_append_object.class differ
diff --git a/regression/strings/performance_tests/java_append_object/test_append_object.java b/regression/strings/performance_tests/java_append_object/test_append_object.java
new file mode 100644
index 00000000000..e139a01679a
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_object/test_append_object.java
@@ -0,0 +1,17 @@
+public class test_append_object
+{
+   public static void main(/*String[] args*/)
+   {
+      Object diff = "diff";
+      Object blue = "blue";
+
+      StringBuilder buffer = new StringBuilder();
+
+      buffer.append(diff)
+            .append(blue);
+
+      String tmp=buffer.toString();
+      System.out.println(tmp);
+      assert(!tmp.equals("diffblue"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_append_string/test.desc b/regression/strings/performance_tests/java_append_string/test.desc
new file mode 100644
index 00000000000..ed5b593bd66
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_string/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_string.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 12.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_append_string/test_append_string.class b/regression/strings/performance_tests/java_append_string/test_append_string.class
new file mode 100644
index 00000000000..f2cb5cf8bea
Binary files /dev/null and b/regression/strings/performance_tests/java_append_string/test_append_string.class differ
diff --git a/regression/strings/performance_tests/java_append_string/test_append_string.java b/regression/strings/performance_tests/java_append_string/test_append_string.java
new file mode 100644
index 00000000000..54665da29cc
--- /dev/null
+++ b/regression/strings/performance_tests/java_append_string/test_append_string.java
@@ -0,0 +1,14 @@
+public class test_append_string
+{
+   public static void main(/*String[] args*/)
+   {
+      String di = new String("di");
+      StringBuilder diff = new StringBuilder();
+      diff.append(di);
+      diff.append("ff");
+      System.out.println(diff);
+      String s = diff.toString();
+      System.out.println(s);
+      assert (!s.equals("diff"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_case/test.desc b/regression/strings/performance_tests/java_case/test.desc
new file mode 100644
index 00000000000..9a90f47dafc
--- /dev/null
+++ b/regression/strings/performance_tests/java_case/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_case.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_case/test_case.class b/regression/strings/performance_tests/java_case/test_case.class
new file mode 100644
index 00000000000..5887b496986
Binary files /dev/null and b/regression/strings/performance_tests/java_case/test_case.class differ
diff --git a/regression/strings/performance_tests/java_case/test_case.java b/regression/strings/performance_tests/java_case/test_case.java
new file mode 100644
index 00000000000..309abfc07b9
--- /dev/null
+++ b/regression/strings/performance_tests/java_case/test_case.java
@@ -0,0 +1,12 @@
+public class test_case
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Ab");
+      String l = s.toLowerCase();
+      String u = s.toUpperCase();
+      assert(!l.equals("ab") ||
+             !u.equals("AB") ||
+             !s.equalsIgnoreCase("aB"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_char_array/test.desc b/regression/strings/performance_tests/java_char_array/test.desc
new file mode 100644
index 00000000000..bf03b8ecf4f
--- /dev/null
+++ b/regression/strings/performance_tests/java_char_array/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_char_array.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_char_array/test_char_array.class b/regression/strings/performance_tests/java_char_array/test_char_array.class
new file mode 100644
index 00000000000..38a7ecf41ed
Binary files /dev/null and b/regression/strings/performance_tests/java_char_array/test_char_array.class differ
diff --git a/regression/strings/performance_tests/java_char_array/test_char_array.java b/regression/strings/performance_tests/java_char_array/test_char_array.java
new file mode 100644
index 00000000000..96e250fb030
--- /dev/null
+++ b/regression/strings/performance_tests/java_char_array/test_char_array.java
@@ -0,0 +1,13 @@
+public class test_char_array
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "abc";
+      char [] str = s.toCharArray();
+      char c = str[2];
+      char a = s.charAt(0);
+      assert(str.length != 3 ||
+             a != 'a' ||
+             c != 'c');
+   }
+}
diff --git a/regression/strings/performance_tests/java_char_array_init/test.desc b/regression/strings/performance_tests/java_char_array_init/test.desc
new file mode 100644
index 00000000000..e3d08208c4e
--- /dev/null
+++ b/regression/strings/performance_tests/java_char_array_init/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_init.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 14.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_char_array_init/test_init.class b/regression/strings/performance_tests/java_char_array_init/test_init.class
new file mode 100644
index 00000000000..ff9c64510da
Binary files /dev/null and b/regression/strings/performance_tests/java_char_array_init/test_init.class differ
diff --git a/regression/strings/performance_tests/java_char_array_init/test_init.java b/regression/strings/performance_tests/java_char_array_init/test_init.java
new file mode 100644
index 00000000000..b27030b1306
--- /dev/null
+++ b/regression/strings/performance_tests/java_char_array_init/test_init.java
@@ -0,0 +1,18 @@
+public class test_init {
+
+  public static void main(/*String[] argv*/)
+  {
+     char [] str = new char[10];
+     str[0] = 'H';
+     str[1] = 'e';
+     str[2] = 'l';
+     str[3] = 'l';
+     str[4] = 'o';
+     String s = new String(str);
+     String t = new String(str,1,2);
+
+     assert(s.length() != 10 || 
+            !t.equals("el") ||
+            !s.startsWith("Hello"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_char_at/test.desc b/regression/strings/performance_tests/java_char_at/test.desc
new file mode 100644
index 00000000000..477c006b597
--- /dev/null
+++ b/regression/strings/performance_tests/java_char_at/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_char_at.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 5.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_char_at/test_char_at.class b/regression/strings/performance_tests/java_char_at/test_char_at.class
new file mode 100644
index 00000000000..dc9ed32f19f
Binary files /dev/null and b/regression/strings/performance_tests/java_char_at/test_char_at.class differ
diff --git a/regression/strings/performance_tests/java_char_at/test_char_at.java b/regression/strings/performance_tests/java_char_at/test_char_at.java
new file mode 100644
index 00000000000..9ae02733fb8
--- /dev/null
+++ b/regression/strings/performance_tests/java_char_at/test_char_at.java
@@ -0,0 +1,7 @@
+public class test_char_at {
+
+  public static void main(/*String[] argv*/) {
+    String s = new String("abc");
+    assert(s.charAt(2)!='c');
+  }
+}
diff --git a/regression/strings/performance_tests/java_code_point/test.desc b/regression/strings/performance_tests/java_code_point/test.desc
new file mode 100644
index 00000000000..d10b960e1d9
--- /dev/null
+++ b/regression/strings/performance_tests/java_code_point/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_code_point.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_code_point/test_code_point.class b/regression/strings/performance_tests/java_code_point/test_code_point.class
new file mode 100644
index 00000000000..f2f5fbad63a
Binary files /dev/null and b/regression/strings/performance_tests/java_code_point/test_code_point.class differ
diff --git a/regression/strings/performance_tests/java_code_point/test_code_point.java b/regression/strings/performance_tests/java_code_point/test_code_point.java
new file mode 100644
index 00000000000..345dc1fa08b
--- /dev/null
+++ b/regression/strings/performance_tests/java_code_point/test_code_point.java
@@ -0,0 +1,14 @@
+public class test_code_point
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "!𐤇𐤄𐤋𐤋𐤅";
+      StringBuilder sb = new StringBuilder();
+      sb.appendCodePoint(0x10907);
+      assert(s.codePointAt(1) != 67847 ||
+             s.codePointBefore(3) != 67847 ||
+             s.codePointCount(1,5) < 2 ||
+             s.offsetByCodePoints(1,2) < 3  ||
+             s.charAt(1) != sb.charAt(0));
+   }
+}
diff --git a/regression/strings/performance_tests/java_compare/test.desc b/regression/strings/performance_tests/java_compare/test.desc
new file mode 100644
index 00000000000..351eb7f4536
--- /dev/null
+++ b/regression/strings/performance_tests/java_compare/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_compare.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 7.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_compare/test_compare.class b/regression/strings/performance_tests/java_compare/test_compare.class
new file mode 100644
index 00000000000..67f18914ea6
Binary files /dev/null and b/regression/strings/performance_tests/java_compare/test_compare.class differ
diff --git a/regression/strings/performance_tests/java_compare/test_compare.java b/regression/strings/performance_tests/java_compare/test_compare.java
new file mode 100644
index 00000000000..0a535fd0bf3
--- /dev/null
+++ b/regression/strings/performance_tests/java_compare/test_compare.java
@@ -0,0 +1,9 @@
+public class test_compare
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s1 = "ab";
+      String s2 = "aa";
+      assert(s1.compareTo(s2) != 1);
+   }
+}
diff --git a/regression/strings/performance_tests/java_concat/test.desc b/regression/strings/performance_tests/java_concat/test.desc
new file mode 100644
index 00000000000..9bfb8fb9ced
--- /dev/null
+++ b/regression/strings/performance_tests/java_concat/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_concat.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 10.* SUCCESS$
+^\[.*assertion.2\].* line 11.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_concat/test_concat.class b/regression/strings/performance_tests/java_concat/test_concat.class
new file mode 100644
index 00000000000..a69c05921f6
Binary files /dev/null and b/regression/strings/performance_tests/java_concat/test_concat.class differ
diff --git a/regression/strings/performance_tests/java_concat/test_concat.java b/regression/strings/performance_tests/java_concat/test_concat.java
new file mode 100644
index 00000000000..6bbe753b2e4
--- /dev/null
+++ b/regression/strings/performance_tests/java_concat/test_concat.java
@@ -0,0 +1,13 @@
+public class test_concat
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("pi");
+      int i = s.length();
+      String t = new String("ppo");
+      String u = s.concat(t);
+      char c = u.charAt(i);
+      assert(c == 'p');
+      assert(c != 'p');
+   }
+}
diff --git a/regression/strings/performance_tests/java_contains/test.desc b/regression/strings/performance_tests/java_contains/test.desc
new file mode 100644
index 00000000000..95576273607
--- /dev/null
+++ b/regression/strings/performance_tests/java_contains/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_contains.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 7.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_contains/test_contains.class b/regression/strings/performance_tests/java_contains/test_contains.class
new file mode 100644
index 00000000000..9bbccb03775
Binary files /dev/null and b/regression/strings/performance_tests/java_contains/test_contains.class differ
diff --git a/regression/strings/performance_tests/java_contains/test_contains.java b/regression/strings/performance_tests/java_contains/test_contains.java
new file mode 100644
index 00000000000..6f4c60a1a2e
--- /dev/null
+++ b/regression/strings/performance_tests/java_contains/test_contains.java
@@ -0,0 +1,9 @@
+public class test_contains
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abc");
+      String u = "bc";
+      assert(!s.contains(u));
+   }
+}
diff --git a/regression/strings/performance_tests/java_delete/test.desc b/regression/strings/performance_tests/java_delete/test.desc
new file mode 100644
index 00000000000..0ac1a72411b
--- /dev/null
+++ b/regression/strings/performance_tests/java_delete/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_delete.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_delete/test_delete.class b/regression/strings/performance_tests/java_delete/test_delete.class
new file mode 100644
index 00000000000..7036ce13c90
Binary files /dev/null and b/regression/strings/performance_tests/java_delete/test_delete.class differ
diff --git a/regression/strings/performance_tests/java_delete/test_delete.java b/regression/strings/performance_tests/java_delete/test_delete.java
new file mode 100644
index 00000000000..ea846cd215a
--- /dev/null
+++ b/regression/strings/performance_tests/java_delete/test_delete.java
@@ -0,0 +1,10 @@
+public class test_delete
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder s = new StringBuilder("Abc");
+      s.delete(1,2);
+      String str = s.toString();
+      assert(!str.equals("Ac"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_delete_char_at/test.desc b/regression/strings/performance_tests/java_delete_char_at/test.desc
new file mode 100644
index 00000000000..8dc189360ff
--- /dev/null
+++ b/regression/strings/performance_tests/java_delete_char_at/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_delete_char_at.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_delete_char_at/test_delete_char_at.class b/regression/strings/performance_tests/java_delete_char_at/test_delete_char_at.class
new file mode 100644
index 00000000000..ed3148e2f7e
Binary files /dev/null and b/regression/strings/performance_tests/java_delete_char_at/test_delete_char_at.class differ
diff --git a/regression/strings/performance_tests/java_delete_char_at/test_delete_char_at.java b/regression/strings/performance_tests/java_delete_char_at/test_delete_char_at.java
new file mode 100644
index 00000000000..5f2c995b56b
--- /dev/null
+++ b/regression/strings/performance_tests/java_delete_char_at/test_delete_char_at.java
@@ -0,0 +1,11 @@
+public class test_delete_char_at
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder s = new StringBuilder();
+      s.append("Abc");
+      s.deleteCharAt(1);
+      String str = s.toString();
+      assert(!str.equals("Ac"));
+   }
+}
diff --git a/regression/strings/java_easychair/easychair.class b/regression/strings/performance_tests/java_easychair/easychair.class
similarity index 84%
rename from regression/strings/java_easychair/easychair.class
rename to regression/strings/performance_tests/java_easychair/easychair.class
index e47900cc0b2..e6c5f66c42d 100644
Binary files a/regression/strings/java_easychair/easychair.class and b/regression/strings/performance_tests/java_easychair/easychair.class differ
diff --git a/regression/strings/performance_tests/java_easychair/easychair.java b/regression/strings/performance_tests/java_easychair/easychair.java
new file mode 100644
index 00000000000..caed962fb46
--- /dev/null
+++ b/regression/strings/performance_tests/java_easychair/easychair.java
@@ -0,0 +1,34 @@
+public class easychair
+{
+   public static void main(String[] argv)
+   {
+      if(argv.length > 1)
+      {
+         String str = new String(argv[1]);
+         if(str.length() < 40)
+         {
+            // containing "/" and containing "EasyChair"
+            int lastSlash = str.lastIndexOf('/');
+            if(lastSlash < 0) return ;
+
+            String rest = str.substring(lastSlash + 1);
+            // warning: removed this because contains is not efficient at the moment
+            if(! rest.contains("EasyChair")) return ;
+            // (2) Check that str starts with "http://"
+            if(! str.startsWith("http://")) return ;
+            // (3) Take the string between "http://" and the last "/".
+            // if it starts with "www." strip the "www." off
+            String t = str.substring("http://".length(),lastSlash - "http://".length());
+            if(t.startsWith("www."))
+            t = t.substring("www.".length());
+
+            //(4) Check that after stripping we have either "live.com"
+            // or "google.com"
+            if(!t.equals("live.com") && !t.equals("google.com"))
+               return ;
+            // s survived all checks
+            assert(false); //return true;
+         }
+      }
+   }
+}
diff --git a/regression/strings/performance_tests/java_easychair/test.desc b/regression/strings/performance_tests/java_easychair/test.desc
new file mode 100644
index 00000000000..a7fff1aa0ac
--- /dev/null
+++ b/regression/strings/performance_tests/java_easychair/test.desc
@@ -0,0 +1,7 @@
+THOROUGH
+easychair.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 30.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_empty/test.desc b/regression/strings/performance_tests/java_empty/test.desc
new file mode 100644
index 00000000000..eabc07fed57
--- /dev/null
+++ b/regression/strings/performance_tests/java_empty/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_empty.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 6.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_empty/test_empty.class b/regression/strings/performance_tests/java_empty/test_empty.class
new file mode 100644
index 00000000000..147a2b628fe
Binary files /dev/null and b/regression/strings/performance_tests/java_empty/test_empty.class differ
diff --git a/regression/strings/performance_tests/java_empty/test_empty.java b/regression/strings/performance_tests/java_empty/test_empty.java
new file mode 100644
index 00000000000..18fde4a115e
--- /dev/null
+++ b/regression/strings/performance_tests/java_empty/test_empty.java
@@ -0,0 +1,8 @@
+public class test_empty
+{
+   public static void main(/*String[] argv*/)
+   {
+      String empty = "";
+      assert(!empty.isEmpty());
+   }
+}
diff --git a/regression/strings/performance_tests/java_endswith/test.desc b/regression/strings/performance_tests/java_endswith/test.desc
new file mode 100644
index 00000000000..25f4b7cac14
--- /dev/null
+++ b/regression/strings/performance_tests/java_endswith/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_endswith.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 7.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_endswith/test_endswith.class b/regression/strings/performance_tests/java_endswith/test_endswith.class
new file mode 100644
index 00000000000..e3d453c444f
Binary files /dev/null and b/regression/strings/performance_tests/java_endswith/test_endswith.class differ
diff --git a/regression/strings/performance_tests/java_endswith/test_endswith.java b/regression/strings/performance_tests/java_endswith/test_endswith.java
new file mode 100644
index 00000000000..fabf6f8dde0
--- /dev/null
+++ b/regression/strings/performance_tests/java_endswith/test_endswith.java
@@ -0,0 +1,9 @@
+public class test_endswith
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abcd");
+      String suff = "cd";
+      assert(!s.endsWith(suff));
+   }
+}
diff --git a/regression/strings/performance_tests/java_equal/test.desc b/regression/strings/performance_tests/java_equal/test.desc
new file mode 100644
index 00000000000..a72c9315fd2
--- /dev/null
+++ b/regression/strings/performance_tests/java_equal/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_equal.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/java_equal/test_equal.class b/regression/strings/performance_tests/java_equal/test_equal.class
similarity index 77%
rename from regression/strings/java_equal/test_equal.class
rename to regression/strings/performance_tests/java_equal/test_equal.class
index 26ee19e6cb1..e0fc6db8aaf 100644
Binary files a/regression/strings/java_equal/test_equal.class and b/regression/strings/performance_tests/java_equal/test_equal.class differ
diff --git a/regression/strings/performance_tests/java_equal/test_equal.java b/regression/strings/performance_tests/java_equal/test_equal.java
new file mode 100644
index 00000000000..e8c9ac7cb1a
--- /dev/null
+++ b/regression/strings/performance_tests/java_equal/test_equal.java
@@ -0,0 +1,9 @@
+public class test_equal
+{
+   public static void main(String[] argv)
+   {
+      String s = new String("pi");
+      String t = new String("po");
+      assert(!s.equals(t));
+   }
+}
diff --git a/regression/strings/performance_tests/java_float/test.desc b/regression/strings/performance_tests/java_float/test.desc
new file mode 100644
index 00000000000..4acb121e634
--- /dev/null
+++ b/regression/strings/performance_tests/java_float/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_float.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 15.* FAILURE$
+--
diff --git a/regression/strings/java_float/test_float.class b/regression/strings/performance_tests/java_float/test_float.class
similarity index 57%
rename from regression/strings/java_float/test_float.class
rename to regression/strings/performance_tests/java_float/test_float.class
index 356d0e17871..00e8622e2ac 100644
Binary files a/regression/strings/java_float/test_float.class and b/regression/strings/performance_tests/java_float/test_float.class differ
diff --git a/regression/strings/performance_tests/java_float/test_float.java b/regression/strings/performance_tests/java_float/test_float.java
new file mode 100644
index 00000000000..312f1aeaf10
--- /dev/null
+++ b/regression/strings/performance_tests/java_float/test_float.java
@@ -0,0 +1,17 @@
+public class test_float
+{
+   public static void main(/*String[] arg*/)
+   {
+      float inf = 100.0f / 0.0f;
+      float minus_inf = -100.0f / 0.0f;
+      float nan = 0.0f / 0.0f;
+      String inf_string = Float.toString(inf);
+      String mininf_string = Float.toString(minus_inf);
+      String nan_string = Float.toString(nan);
+      System.out.println(nan_string);
+      System.out.println(inf_string);
+      System.out.println(mininf_string);
+      assert(!nan_string.equals("NaN") || !inf_string.equals("Infinity")
+             || !mininf_string.equals("-Infinity"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_hash_code/test.desc b/regression/strings/performance_tests/java_hash_code/test.desc
new file mode 100644
index 00000000000..313c5e4104c
--- /dev/null
+++ b/regression/strings/performance_tests/java_hash_code/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_hash_code.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 7.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_hash_code/test_hash_code.class b/regression/strings/performance_tests/java_hash_code/test_hash_code.class
new file mode 100644
index 00000000000..d9b3e2b2f3d
Binary files /dev/null and b/regression/strings/performance_tests/java_hash_code/test_hash_code.class differ
diff --git a/regression/strings/performance_tests/java_hash_code/test_hash_code.java b/regression/strings/performance_tests/java_hash_code/test_hash_code.java
new file mode 100644
index 00000000000..fbc15f0b4c2
--- /dev/null
+++ b/regression/strings/performance_tests/java_hash_code/test_hash_code.java
@@ -0,0 +1,9 @@
+public class test_hash_code
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s1 = "ab";
+      String s2 = "ab";
+      assert(s1.hashCode() != s2.hashCode());
+   }
+}
diff --git a/regression/strings/performance_tests/java_index_of/test.desc b/regression/strings/performance_tests/java_index_of/test.desc
new file mode 100644
index 00000000000..2651a60d73f
--- /dev/null
+++ b/regression/strings/performance_tests/java_index_of/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_index_of.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_index_of/test_index_of.class b/regression/strings/performance_tests/java_index_of/test_index_of.class
new file mode 100644
index 00000000000..cae397a79fb
Binary files /dev/null and b/regression/strings/performance_tests/java_index_of/test_index_of.class differ
diff --git a/regression/strings/performance_tests/java_index_of/test_index_of.java b/regression/strings/performance_tests/java_index_of/test_index_of.java
new file mode 100644
index 00000000000..b607ba79570
--- /dev/null
+++ b/regression/strings/performance_tests/java_index_of/test_index_of.java
@@ -0,0 +1,10 @@
+public class test_index_of
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "Abc";
+      String bc = "bc";
+      int i = s.indexOf(bc);
+      assert(i != 1);
+   }
+}
diff --git a/regression/strings/performance_tests/java_index_of_char/test.desc b/regression/strings/performance_tests/java_index_of_char/test.desc
new file mode 100644
index 00000000000..e1159295558
--- /dev/null
+++ b/regression/strings/performance_tests/java_index_of_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_index_of_char.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_index_of_char/test_index_of_char.class b/regression/strings/performance_tests/java_index_of_char/test_index_of_char.class
new file mode 100644
index 00000000000..bf4fa6e946e
Binary files /dev/null and b/regression/strings/performance_tests/java_index_of_char/test_index_of_char.class differ
diff --git a/regression/strings/performance_tests/java_index_of_char/test_index_of_char.java b/regression/strings/performance_tests/java_index_of_char/test_index_of_char.java
new file mode 100644
index 00000000000..92d75b3b07d
--- /dev/null
+++ b/regression/strings/performance_tests/java_index_of_char/test_index_of_char.java
@@ -0,0 +1,10 @@
+public class test_index_of_char
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "Abc";
+      char c = 'c';
+      int i = s.indexOf(c);
+      assert(i != 2);
+   }
+}
diff --git a/regression/strings/performance_tests/java_insert_char/test.desc b/regression/strings/performance_tests/java_insert_char/test.desc
new file mode 100644
index 00000000000..8056f171ad1
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_char.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_insert_char/test_insert_char.class b/regression/strings/performance_tests/java_insert_char/test_insert_char.class
new file mode 100644
index 00000000000..fbf4a82070b
Binary files /dev/null and b/regression/strings/performance_tests/java_insert_char/test_insert_char.class differ
diff --git a/regression/strings/performance_tests/java_insert_char/test_insert_char.java b/regression/strings/performance_tests/java_insert_char/test_insert_char.java
new file mode 100644
index 00000000000..3a83f03b332
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_char/test_insert_char.java
@@ -0,0 +1,10 @@
+public class test_insert_char
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ac");
+      sb.insert(1, 'b');
+      String s = sb.toString();
+      assert(!s.equals("abc"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_insert_char_array/test.desc b/regression/strings/performance_tests/java_insert_char_array/test.desc
new file mode 100644
index 00000000000..17d5e5da8d5
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_char_array/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_char_array.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 12.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_insert_char_array/test_insert_char_array.class b/regression/strings/performance_tests/java_insert_char_array/test_insert_char_array.class
new file mode 100644
index 00000000000..bc1a23a7496
Binary files /dev/null and b/regression/strings/performance_tests/java_insert_char_array/test_insert_char_array.class differ
diff --git a/regression/strings/performance_tests/java_insert_char_array/test_insert_char_array.java b/regression/strings/performance_tests/java_insert_char_array/test_insert_char_array.java
new file mode 100644
index 00000000000..079dbd2fee6
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_char_array/test_insert_char_array.java
@@ -0,0 +1,14 @@
+public class test_insert_char_array
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ad");
+      char[] array = new char[2];
+      array[0] = 'b';
+      array[1] = 'c';
+      sb.insert(1, array);
+      String s = sb.toString();
+      System.out.println(s);
+      assert(!s.equals("abcd"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_insert_int/test.desc b/regression/strings/performance_tests/java_insert_int/test.desc
new file mode 100644
index 00000000000..8158b444763
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_int/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_int.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_insert_int/test_insert_int.class b/regression/strings/performance_tests/java_insert_int/test_insert_int.class
new file mode 100644
index 00000000000..cd355c86546
Binary files /dev/null and b/regression/strings/performance_tests/java_insert_int/test_insert_int.class differ
diff --git a/regression/strings/performance_tests/java_insert_int/test_insert_int.java b/regression/strings/performance_tests/java_insert_int/test_insert_int.java
new file mode 100644
index 00000000000..15a7a2d53f6
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_int/test_insert_int.java
@@ -0,0 +1,10 @@
+public class test_insert_int
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ac");
+      sb.insert(1, 42);
+      String s = sb.toString();
+      assert(!s.equals("a42c"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_insert_multiple/test.desc b/regression/strings/performance_tests/java_insert_multiple/test.desc
new file mode 100644
index 00000000000..2aeab10a917
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_multiple/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_multiple.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_insert_multiple/test_insert_multiple.class b/regression/strings/performance_tests/java_insert_multiple/test_insert_multiple.class
new file mode 100644
index 00000000000..d6b470a1f72
Binary files /dev/null and b/regression/strings/performance_tests/java_insert_multiple/test_insert_multiple.class differ
diff --git a/regression/strings/performance_tests/java_insert_multiple/test_insert_multiple.java b/regression/strings/performance_tests/java_insert_multiple/test_insert_multiple.java
new file mode 100644
index 00000000000..c976ddd807f
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_multiple/test_insert_multiple.java
@@ -0,0 +1,11 @@
+public class test_insert_multiple
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ad");
+      sb.insert(1, 'c');
+      sb.insert(1, "b");
+      String s = sb.toString();
+      assert(!s.equals("abcd"));
+   }
+}
diff --git a/regression/strings/performance_tests/java_insert_string/test.desc b/regression/strings/performance_tests/java_insert_string/test.desc
new file mode 100644
index 00000000000..4df1aeedf35
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_string/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_string.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/performance_tests/java_insert_string/test_insert_string.class b/regression/strings/performance_tests/java_insert_string/test_insert_string.class
new file mode 100644
index 00000000000..be8f7ad0f79
Binary files /dev/null and b/regression/strings/performance_tests/java_insert_string/test_insert_string.class differ
diff --git a/regression/strings/performance_tests/java_insert_string/test_insert_string.java b/regression/strings/performance_tests/java_insert_string/test_insert_string.java
new file mode 100644
index 00000000000..028a348122b
--- /dev/null
+++ b/regression/strings/performance_tests/java_insert_string/test_insert_string.java
@@ -0,0 +1,10 @@
+public class test_insert_string
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ad");
+      sb.insert(1, "bc");
+      String s = sb.toString();
+      assert(!s.equals("abcd"));
+   }
+}
diff --git a/regression/strings/smoke_tests/Makefile b/regression/strings/smoke_tests/Makefile
new file mode 100644
index 00000000000..185be13bd7b
--- /dev/null
+++ b/regression/strings/smoke_tests/Makefile
@@ -0,0 +1,9 @@
+
+test:
+	@../../test.pl -c ../../../../src/cbmc/cbmc
+
+testfuture:
+	@../../test.pl -c ../../../../src/cbmc/cbmc -CF
+
+testall:
+	@../../test.pl -c ../../../../src/cbmc/cbmc -CFTK
diff --git a/regression/strings/smoke_tests/java_append_char/test.desc b/regression/strings/smoke_tests/java_append_char/test.desc
new file mode 100644
index 00000000000..afedb9a2fa0
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_char.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_append_char/test_append_char.class b/regression/strings/smoke_tests/java_append_char/test_append_char.class
new file mode 100644
index 00000000000..00c40aef6f6
Binary files /dev/null and b/regression/strings/smoke_tests/java_append_char/test_append_char.class differ
diff --git a/regression/strings/smoke_tests/java_append_char/test_append_char.java b/regression/strings/smoke_tests/java_append_char/test_append_char.java
new file mode 100644
index 00000000000..3eec4f30abe
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_char/test_append_char.java
@@ -0,0 +1,17 @@
+public class test_append_char
+{
+   public static void main(/*String[] args*/)
+   {
+      char[] diff = {'d', 'i', 'f', 'f'};
+      char[] blue = {'b', 'l', 'u', 'e'};
+
+      StringBuilder buffer = new StringBuilder();
+
+      buffer.append(diff)
+            .append(blue);
+
+      String tmp=buffer.toString();
+      System.out.println(tmp);
+      assert tmp.equals("diffblue");
+   }
+}
diff --git a/regression/strings/smoke_tests/java_append_int/test.desc b/regression/strings/smoke_tests/java_append_int/test.desc
new file mode 100644
index 00000000000..d72294910fd
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_int/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_int.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_append_int/test_append_int.class b/regression/strings/smoke_tests/java_append_int/test_append_int.class
new file mode 100644
index 00000000000..16948397e03
Binary files /dev/null and b/regression/strings/smoke_tests/java_append_int/test_append_int.class differ
diff --git a/regression/strings/smoke_tests/java_append_int/test_append_int.java b/regression/strings/smoke_tests/java_append_int/test_append_int.java
new file mode 100644
index 00000000000..963f3d7c063
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_int/test_append_int.java
@@ -0,0 +1,11 @@
+public class test_append_int
+{
+   public static void main(/*String[] args*/)
+   {
+      StringBuilder diffblue = new StringBuilder();
+      diffblue.append("d");
+      diffblue.append(4);
+      String s = diffblue.toString();
+      assert s.equals("d4");
+   }
+}
diff --git a/regression/strings/smoke_tests/java_append_object/test.desc b/regression/strings/smoke_tests/java_append_object/test.desc
new file mode 100644
index 00000000000..dfc96352e21
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_object/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_object.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_append_object/test_append_object.class b/regression/strings/smoke_tests/java_append_object/test_append_object.class
new file mode 100644
index 00000000000..ed6942a1fa6
Binary files /dev/null and b/regression/strings/smoke_tests/java_append_object/test_append_object.class differ
diff --git a/regression/strings/smoke_tests/java_append_object/test_append_object.java b/regression/strings/smoke_tests/java_append_object/test_append_object.java
new file mode 100644
index 00000000000..121690451ca
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_object/test_append_object.java
@@ -0,0 +1,17 @@
+public class test_append_object
+{
+   public static void main(/*String[] args*/)
+   {
+      Object diff = "diff";
+      Object blue = "blue";
+
+      StringBuilder buffer = new StringBuilder();
+
+      buffer.append(diff)
+            .append(blue);
+
+      String tmp=buffer.toString();
+      System.out.println(tmp);
+      assert tmp.equals("diffblue");
+   }
+}
diff --git a/regression/strings/smoke_tests/java_append_string/test.desc b/regression/strings/smoke_tests/java_append_string/test.desc
new file mode 100644
index 00000000000..52db03ff482
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_string/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_append_string.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_append_string/test_append_string.class b/regression/strings/smoke_tests/java_append_string/test_append_string.class
new file mode 100644
index 00000000000..622e08467f9
Binary files /dev/null and b/regression/strings/smoke_tests/java_append_string/test_append_string.class differ
diff --git a/regression/strings/smoke_tests/java_append_string/test_append_string.java b/regression/strings/smoke_tests/java_append_string/test_append_string.java
new file mode 100644
index 00000000000..e7f961172fa
--- /dev/null
+++ b/regression/strings/smoke_tests/java_append_string/test_append_string.java
@@ -0,0 +1,14 @@
+public class test_append_string
+{
+   public static void main(/*String[] args*/)
+   {
+      String di = new String("di");
+      StringBuilder diff = new StringBuilder();
+      diff.append(di);
+      diff.append("ff");
+      System.out.println(diff);
+      String s = diff.toString();
+      System.out.println(s);
+      assert s.equals("diff");
+   }
+}
diff --git a/regression/strings/smoke_tests/java_case/test.desc b/regression/strings/smoke_tests/java_case/test.desc
new file mode 100644
index 00000000000..56568251dcd
--- /dev/null
+++ b/regression/strings/smoke_tests/java_case/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_case.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_case/test_case.class b/regression/strings/smoke_tests/java_case/test_case.class
new file mode 100644
index 00000000000..9f7eaab446c
Binary files /dev/null and b/regression/strings/smoke_tests/java_case/test_case.class differ
diff --git a/regression/strings/smoke_tests/java_case/test_case.java b/regression/strings/smoke_tests/java_case/test_case.java
new file mode 100644
index 00000000000..b3437a6f83e
--- /dev/null
+++ b/regression/strings/smoke_tests/java_case/test_case.java
@@ -0,0 +1,12 @@
+public class test_case
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Ab");
+      String l = s.toLowerCase();
+      String u = s.toUpperCase();
+      assert(l.equals("ab"));
+      assert(u.equals("AB"));
+      assert(s.equalsIgnoreCase("aB"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_char_array/test.desc b/regression/strings/smoke_tests/java_char_array/test.desc
new file mode 100644
index 00000000000..22ca7708ef2
--- /dev/null
+++ b/regression/strings/smoke_tests/java_char_array/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_char_array.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_char_array/test_char_array.class b/regression/strings/smoke_tests/java_char_array/test_char_array.class
new file mode 100644
index 00000000000..0d2056042ca
Binary files /dev/null and b/regression/strings/smoke_tests/java_char_array/test_char_array.class differ
diff --git a/regression/strings/smoke_tests/java_char_array/test_char_array.java b/regression/strings/smoke_tests/java_char_array/test_char_array.java
new file mode 100644
index 00000000000..017fe704124
--- /dev/null
+++ b/regression/strings/smoke_tests/java_char_array/test_char_array.java
@@ -0,0 +1,13 @@
+public class test_char_array
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "abc";
+      char [] str = s.toCharArray();
+      char c = str[2];
+      char a = s.charAt(0);
+      assert(str.length == 3);
+      assert(a == 'a');
+      assert(c == 'c');
+   }
+}
diff --git a/regression/strings/smoke_tests/java_char_array_init/test.desc b/regression/strings/smoke_tests/java_char_array_init/test.desc
new file mode 100644
index 00000000000..94d8faa7afc
--- /dev/null
+++ b/regression/strings/smoke_tests/java_char_array_init/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_init.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_char_array_init/test_init.class b/regression/strings/smoke_tests/java_char_array_init/test_init.class
new file mode 100644
index 00000000000..48075eb9187
Binary files /dev/null and b/regression/strings/smoke_tests/java_char_array_init/test_init.class differ
diff --git a/regression/strings/smoke_tests/java_char_array_init/test_init.java b/regression/strings/smoke_tests/java_char_array_init/test_init.java
new file mode 100644
index 00000000000..8e0f656e3e8
--- /dev/null
+++ b/regression/strings/smoke_tests/java_char_array_init/test_init.java
@@ -0,0 +1,21 @@
+public class test_init {
+
+  public static void main(/*String[] argv*/)
+  {
+     char [] str = new char[10];
+     str[0] = 'H';
+     str[1] = 'e';
+     str[2] = 'l';
+     str[3] = 'l';
+     str[4] = 'o';
+     String s = new String(str);
+     String t = new String(str,1,2);
+
+     System.out.println(s.length());
+     assert(s.length() == 10);
+     System.out.println(s);
+     System.out.println(t);
+     assert(t.equals("el"));
+     assert(s.startsWith("Hello"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_char_at/test.desc b/regression/strings/smoke_tests/java_char_at/test.desc
new file mode 100644
index 00000000000..0f8bcdf6e8f
--- /dev/null
+++ b/regression/strings/smoke_tests/java_char_at/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_char_at.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_char_at/test_char_at.class b/regression/strings/smoke_tests/java_char_at/test_char_at.class
new file mode 100644
index 00000000000..de5fe888245
Binary files /dev/null and b/regression/strings/smoke_tests/java_char_at/test_char_at.class differ
diff --git a/regression/strings/smoke_tests/java_char_at/test_char_at.java b/regression/strings/smoke_tests/java_char_at/test_char_at.java
new file mode 100644
index 00000000000..3b8663d62ae
--- /dev/null
+++ b/regression/strings/smoke_tests/java_char_at/test_char_at.java
@@ -0,0 +1,7 @@
+public class test_char_at {
+
+  public static void main(/*String[] argv*/) {
+    String s = new String("abc");
+    assert(s.charAt(2)=='c');
+  }
+}
diff --git a/regression/strings/smoke_tests/java_code_point/test.desc b/regression/strings/smoke_tests/java_code_point/test.desc
new file mode 100644
index 00000000000..12c9d0f4d60
--- /dev/null
+++ b/regression/strings/smoke_tests/java_code_point/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_code_point.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_code_point/test_code_point.class b/regression/strings/smoke_tests/java_code_point/test_code_point.class
new file mode 100644
index 00000000000..1d5d2269325
Binary files /dev/null and b/regression/strings/smoke_tests/java_code_point/test_code_point.class differ
diff --git a/regression/strings/smoke_tests/java_code_point/test_code_point.java b/regression/strings/smoke_tests/java_code_point/test_code_point.java
new file mode 100644
index 00000000000..faf9a2051d5
--- /dev/null
+++ b/regression/strings/smoke_tests/java_code_point/test_code_point.java
@@ -0,0 +1,14 @@
+public class test_code_point
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "!𐤇𐤄𐤋𐤋𐤅";
+      assert(s.codePointAt(1) == 67847);
+      assert(s.codePointBefore(3) == 67847);
+      assert(s.codePointCount(1,5) >= 2);
+      assert(s.offsetByCodePoints(1,2) >= 3);
+      StringBuilder sb = new StringBuilder();
+      sb.appendCodePoint(0x10907);
+      assert(s.charAt(1) == sb.charAt(0));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_compare/test.desc b/regression/strings/smoke_tests/java_compare/test.desc
new file mode 100644
index 00000000000..76ca1c4c282
--- /dev/null
+++ b/regression/strings/smoke_tests/java_compare/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_compare.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_compare/test_compare.class b/regression/strings/smoke_tests/java_compare/test_compare.class
new file mode 100644
index 00000000000..3a807f4d203
Binary files /dev/null and b/regression/strings/smoke_tests/java_compare/test_compare.class differ
diff --git a/regression/strings/smoke_tests/java_compare/test_compare.java b/regression/strings/smoke_tests/java_compare/test_compare.java
new file mode 100644
index 00000000000..c052ed429bd
--- /dev/null
+++ b/regression/strings/smoke_tests/java_compare/test_compare.java
@@ -0,0 +1,9 @@
+public class test_compare
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s1 = "ab";
+      String s2 = "aa";
+      assert(s1.compareTo(s2) == 1);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_concat/test.desc b/regression/strings/smoke_tests/java_concat/test.desc
new file mode 100644
index 00000000000..9bfb8fb9ced
--- /dev/null
+++ b/regression/strings/smoke_tests/java_concat/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_concat.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 10.* SUCCESS$
+^\[.*assertion.2\].* line 11.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_concat/test_concat.class b/regression/strings/smoke_tests/java_concat/test_concat.class
new file mode 100644
index 00000000000..e4143c15773
Binary files /dev/null and b/regression/strings/smoke_tests/java_concat/test_concat.class differ
diff --git a/regression/strings/smoke_tests/java_concat/test_concat.java b/regression/strings/smoke_tests/java_concat/test_concat.java
new file mode 100644
index 00000000000..b9909c723d4
--- /dev/null
+++ b/regression/strings/smoke_tests/java_concat/test_concat.java
@@ -0,0 +1,13 @@
+public class test_concat
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("pi");
+      int i = s.length();
+      String t = new String("ppo");
+      String u = s.concat(t);
+      char c = u.charAt(i);
+      assert(c == 'p');
+      assert(c == 'o');
+   }
+}
diff --git a/regression/strings/smoke_tests/java_contains/test.desc b/regression/strings/smoke_tests/java_contains/test.desc
new file mode 100644
index 00000000000..169a5f19e73
--- /dev/null
+++ b/regression/strings/smoke_tests/java_contains/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_contains.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* SUCCESS$
+^\[.*assertion.2\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_contains/test_contains.class b/regression/strings/smoke_tests/java_contains/test_contains.class
new file mode 100644
index 00000000000..adf0ece000a
Binary files /dev/null and b/regression/strings/smoke_tests/java_contains/test_contains.class differ
diff --git a/regression/strings/smoke_tests/java_contains/test_contains.java b/regression/strings/smoke_tests/java_contains/test_contains.java
new file mode 100644
index 00000000000..5112c344c09
--- /dev/null
+++ b/regression/strings/smoke_tests/java_contains/test_contains.java
@@ -0,0 +1,11 @@
+public class test_contains
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abc");
+      String u = "bc";
+      String t = "ab";
+      assert(s.contains(u));
+      assert(s.contains(t));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_delete/test.desc b/regression/strings/smoke_tests/java_delete/test.desc
new file mode 100644
index 00000000000..81e6a1a4685
--- /dev/null
+++ b/regression/strings/smoke_tests/java_delete/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_delete.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_delete/test_delete.class b/regression/strings/smoke_tests/java_delete/test_delete.class
new file mode 100644
index 00000000000..f18891851b1
Binary files /dev/null and b/regression/strings/smoke_tests/java_delete/test_delete.class differ
diff --git a/regression/strings/smoke_tests/java_delete/test_delete.java b/regression/strings/smoke_tests/java_delete/test_delete.java
new file mode 100644
index 00000000000..13bd09cd075
--- /dev/null
+++ b/regression/strings/smoke_tests/java_delete/test_delete.java
@@ -0,0 +1,10 @@
+public class test_delete
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder s = new StringBuilder("Abc");
+      s.delete(1,2);
+      String str = s.toString();
+      assert(str.equals("Ac"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_delete_char_at/test.desc b/regression/strings/smoke_tests/java_delete_char_at/test.desc
new file mode 100644
index 00000000000..2d8832804ff
--- /dev/null
+++ b/regression/strings/smoke_tests/java_delete_char_at/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_delete_char_at.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_delete_char_at/test_delete_char_at.class b/regression/strings/smoke_tests/java_delete_char_at/test_delete_char_at.class
new file mode 100644
index 00000000000..cfd8561e596
Binary files /dev/null and b/regression/strings/smoke_tests/java_delete_char_at/test_delete_char_at.class differ
diff --git a/regression/strings/smoke_tests/java_delete_char_at/test_delete_char_at.java b/regression/strings/smoke_tests/java_delete_char_at/test_delete_char_at.java
new file mode 100644
index 00000000000..94787c5283d
--- /dev/null
+++ b/regression/strings/smoke_tests/java_delete_char_at/test_delete_char_at.java
@@ -0,0 +1,11 @@
+public class test_delete_char_at
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder s = new StringBuilder();
+      s.append("Abc");
+      s.deleteCharAt(1);
+      String str = s.toString();
+      assert(str.equals("Ac"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_empty/test.desc b/regression/strings/smoke_tests/java_empty/test.desc
new file mode 100644
index 00000000000..839354fab72
--- /dev/null
+++ b/regression/strings/smoke_tests/java_empty/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_empty.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_empty/test_empty.class b/regression/strings/smoke_tests/java_empty/test_empty.class
new file mode 100644
index 00000000000..8e9a17d387e
Binary files /dev/null and b/regression/strings/smoke_tests/java_empty/test_empty.class differ
diff --git a/regression/strings/smoke_tests/java_empty/test_empty.java b/regression/strings/smoke_tests/java_empty/test_empty.java
new file mode 100644
index 00000000000..47c335e16fa
--- /dev/null
+++ b/regression/strings/smoke_tests/java_empty/test_empty.java
@@ -0,0 +1,8 @@
+public class test_empty
+{
+   public static void main(/*String[] argv*/)
+   {
+      String empty = "";
+      assert(empty.isEmpty());
+   }
+}
diff --git a/regression/strings/smoke_tests/java_endswith/test.desc b/regression/strings/smoke_tests/java_endswith/test.desc
new file mode 100644
index 00000000000..0f094d139b5
--- /dev/null
+++ b/regression/strings/smoke_tests/java_endswith/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_endswith.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 9.* SUCCESS$
+^\[.*assertion.2\].* line 10.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_endswith/test_endswith.class b/regression/strings/smoke_tests/java_endswith/test_endswith.class
new file mode 100644
index 00000000000..1f86e94431d
Binary files /dev/null and b/regression/strings/smoke_tests/java_endswith/test_endswith.class differ
diff --git a/regression/strings/smoke_tests/java_endswith/test_endswith.java b/regression/strings/smoke_tests/java_endswith/test_endswith.java
new file mode 100644
index 00000000000..f7729ef6a40
--- /dev/null
+++ b/regression/strings/smoke_tests/java_endswith/test_endswith.java
@@ -0,0 +1,12 @@
+public class test_endswith
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abcd");
+      String suff = "cd";
+      String bad_suff = "bc";
+
+      assert(s.endsWith(suff));
+      assert(s.endsWith(bad_suff));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_equal/test.desc b/regression/strings/smoke_tests/java_equal/test.desc
new file mode 100644
index 00000000000..b1ccbc69d2d
--- /dev/null
+++ b/regression/strings/smoke_tests/java_equal/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_equal.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* FAILURE$
+^\[.*assertion.2\].* line 9.* SUCCESS$
+--
diff --git a/regression/strings/smoke_tests/java_equal/test_equal.class b/regression/strings/smoke_tests/java_equal/test_equal.class
new file mode 100644
index 00000000000..e0fc6db8aaf
Binary files /dev/null and b/regression/strings/smoke_tests/java_equal/test_equal.class differ
diff --git a/regression/strings/smoke_tests/java_equal/test_equal.java b/regression/strings/smoke_tests/java_equal/test_equal.java
new file mode 100644
index 00000000000..a3acb0ebda5
--- /dev/null
+++ b/regression/strings/smoke_tests/java_equal/test_equal.java
@@ -0,0 +1,11 @@
+public class test_equal
+{
+   public static void main(String[] argv)
+   {
+      String s = new String("pi");
+      String t = new String("po");
+      String u = "po";
+      assert(s.equals(t));
+      assert(t.equals(u));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_float/test.desc b/regression/strings/smoke_tests/java_float/test.desc
new file mode 100644
index 00000000000..09df1150e77
--- /dev/null
+++ b/regression/strings/smoke_tests/java_float/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_float.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_float/test_float.class b/regression/strings/smoke_tests/java_float/test_float.class
new file mode 100644
index 00000000000..e4448d41558
Binary files /dev/null and b/regression/strings/smoke_tests/java_float/test_float.class differ
diff --git a/regression/strings/smoke_tests/java_float/test_float.java b/regression/strings/smoke_tests/java_float/test_float.java
new file mode 100644
index 00000000000..d2791d5c343
--- /dev/null
+++ b/regression/strings/smoke_tests/java_float/test_float.java
@@ -0,0 +1,15 @@
+public class test_float
+{
+   public static void main(/*String[] arg*/)
+   {
+      float inf = 100.0f / 0.0f;
+      float minus_inf = -100.0f / 0.0f;
+      float nan = 0.0f / 0.0f;
+      String inf_string = Float.toString(inf);
+      String mininf_string = Float.toString(minus_inf);
+      String nan_string = Float.toString(nan);
+      assert(nan_string.equals("NaN"));
+      assert(inf_string.equals("Infinity"));
+      assert(mininf_string.equals("-Infinity"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_hash_code/test.desc b/regression/strings/smoke_tests/java_hash_code/test.desc
new file mode 100644
index 00000000000..c1f3f1d57b1
--- /dev/null
+++ b/regression/strings/smoke_tests/java_hash_code/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_hash_code.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* SUCCESS$
+^\[.*assertion.2\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_hash_code/test_hash_code.class b/regression/strings/smoke_tests/java_hash_code/test_hash_code.class
new file mode 100644
index 00000000000..21bc5d96ca9
Binary files /dev/null and b/regression/strings/smoke_tests/java_hash_code/test_hash_code.class differ
diff --git a/regression/strings/smoke_tests/java_hash_code/test_hash_code.java b/regression/strings/smoke_tests/java_hash_code/test_hash_code.java
new file mode 100644
index 00000000000..d9f42b7ff9d
--- /dev/null
+++ b/regression/strings/smoke_tests/java_hash_code/test_hash_code.java
@@ -0,0 +1,11 @@
+public class test_hash_code
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s1 = "ab";
+      String s2 = "ab";
+      String s3 = "aa";
+      assert(s1.hashCode() == s2.hashCode());
+      assert(s1.hashCode() == s3.hashCode());
+   }
+}
diff --git a/regression/strings/smoke_tests/java_index_of/test.desc b/regression/strings/smoke_tests/java_index_of/test.desc
new file mode 100644
index 00000000000..cbed0db8d2e
--- /dev/null
+++ b/regression/strings/smoke_tests/java_index_of/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_index_of.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_index_of/test_index_of.class b/regression/strings/smoke_tests/java_index_of/test_index_of.class
new file mode 100644
index 00000000000..1acb3335d57
Binary files /dev/null and b/regression/strings/smoke_tests/java_index_of/test_index_of.class differ
diff --git a/regression/strings/smoke_tests/java_index_of/test_index_of.java b/regression/strings/smoke_tests/java_index_of/test_index_of.java
new file mode 100644
index 00000000000..270267196c5
--- /dev/null
+++ b/regression/strings/smoke_tests/java_index_of/test_index_of.java
@@ -0,0 +1,10 @@
+public class test_index_of
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "Abc";
+      String bc = "bc";
+      int i = s.indexOf(bc);
+      assert(i == 1);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_index_of_char/test.desc b/regression/strings/smoke_tests/java_index_of_char/test.desc
new file mode 100644
index 00000000000..3a2619c1ecd
--- /dev/null
+++ b/regression/strings/smoke_tests/java_index_of_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_index_of_char.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_index_of_char/test_index_of_char.class b/regression/strings/smoke_tests/java_index_of_char/test_index_of_char.class
new file mode 100644
index 00000000000..f87a1026683
Binary files /dev/null and b/regression/strings/smoke_tests/java_index_of_char/test_index_of_char.class differ
diff --git a/regression/strings/smoke_tests/java_index_of_char/test_index_of_char.java b/regression/strings/smoke_tests/java_index_of_char/test_index_of_char.java
new file mode 100644
index 00000000000..6a5d3d60bd6
--- /dev/null
+++ b/regression/strings/smoke_tests/java_index_of_char/test_index_of_char.java
@@ -0,0 +1,10 @@
+public class test_index_of_char
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "Abc";
+      char c = 'c';
+      int i = s.indexOf(c);
+      assert(i == 2);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_insert_char/test.desc b/regression/strings/smoke_tests/java_insert_char/test.desc
new file mode 100644
index 00000000000..fef348968cb
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_char.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_insert_char/test_insert_char.class b/regression/strings/smoke_tests/java_insert_char/test_insert_char.class
new file mode 100644
index 00000000000..481304a9f6d
Binary files /dev/null and b/regression/strings/smoke_tests/java_insert_char/test_insert_char.class differ
diff --git a/regression/strings/smoke_tests/java_insert_char/test_insert_char.java b/regression/strings/smoke_tests/java_insert_char/test_insert_char.java
new file mode 100644
index 00000000000..ac6beb4ffcf
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_char/test_insert_char.java
@@ -0,0 +1,10 @@
+public class test_insert_char
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ac");
+      sb.insert(1, 'b');
+      String s = sb.toString();
+      assert(s.equals("abc"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_insert_char_array/test.desc b/regression/strings/smoke_tests/java_insert_char_array/test.desc
new file mode 100644
index 00000000000..27c5ef241a1
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_char_array/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_char_array.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_insert_char_array/test_insert_char_array.class b/regression/strings/smoke_tests/java_insert_char_array/test_insert_char_array.class
new file mode 100644
index 00000000000..3c0b5329230
Binary files /dev/null and b/regression/strings/smoke_tests/java_insert_char_array/test_insert_char_array.class differ
diff --git a/regression/strings/smoke_tests/java_insert_char_array/test_insert_char_array.java b/regression/strings/smoke_tests/java_insert_char_array/test_insert_char_array.java
new file mode 100644
index 00000000000..2c2840df672
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_char_array/test_insert_char_array.java
@@ -0,0 +1,14 @@
+public class test_insert_char_array
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ad");
+      char[] array = new char[2];
+      array[0] = 'b';
+      array[1] = 'c';
+      sb.insert(1, array);
+      String s = sb.toString();
+      System.out.println(s);
+      assert(s.equals("abcd"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_insert_int/test.desc b/regression/strings/smoke_tests/java_insert_int/test.desc
new file mode 100644
index 00000000000..3c1a954bf96
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_int/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_int.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_insert_int/test_insert_int.class b/regression/strings/smoke_tests/java_insert_int/test_insert_int.class
new file mode 100644
index 00000000000..8b0121ec681
Binary files /dev/null and b/regression/strings/smoke_tests/java_insert_int/test_insert_int.class differ
diff --git a/regression/strings/smoke_tests/java_insert_int/test_insert_int.java b/regression/strings/smoke_tests/java_insert_int/test_insert_int.java
new file mode 100644
index 00000000000..b787141e51a
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_int/test_insert_int.java
@@ -0,0 +1,10 @@
+public class test_insert_int
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ac");
+      sb.insert(1, 42);
+      String s = sb.toString();
+      assert(s.equals("a42c"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_insert_multiple/.test_insert.java.swp b/regression/strings/smoke_tests/java_insert_multiple/.test_insert.java.swp
new file mode 100644
index 00000000000..5596a2c906d
Binary files /dev/null and b/regression/strings/smoke_tests/java_insert_multiple/.test_insert.java.swp differ
diff --git a/regression/strings/smoke_tests/java_insert_multiple/test.desc b/regression/strings/smoke_tests/java_insert_multiple/test.desc
new file mode 100644
index 00000000000..dc3c5dae10d
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_multiple/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_multiple.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_insert_multiple/test_insert_multiple.class b/regression/strings/smoke_tests/java_insert_multiple/test_insert_multiple.class
new file mode 100644
index 00000000000..17ced6ec67c
Binary files /dev/null and b/regression/strings/smoke_tests/java_insert_multiple/test_insert_multiple.class differ
diff --git a/regression/strings/smoke_tests/java_insert_multiple/test_insert_multiple.java b/regression/strings/smoke_tests/java_insert_multiple/test_insert_multiple.java
new file mode 100644
index 00000000000..cce6881ca7d
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_multiple/test_insert_multiple.java
@@ -0,0 +1,11 @@
+public class test_insert_multiple
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ad");
+      sb.insert(1, 'c');
+      sb.insert(1, "b");
+      String s = sb.toString();
+      assert(s.equals("abcd"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_insert_string/test.desc b/regression/strings/smoke_tests/java_insert_string/test.desc
new file mode 100644
index 00000000000..c8c942bb00e
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_string/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_insert_string.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_insert_string/test_insert_string.class b/regression/strings/smoke_tests/java_insert_string/test_insert_string.class
new file mode 100644
index 00000000000..39cc969a902
Binary files /dev/null and b/regression/strings/smoke_tests/java_insert_string/test_insert_string.class differ
diff --git a/regression/strings/smoke_tests/java_insert_string/test_insert_string.java b/regression/strings/smoke_tests/java_insert_string/test_insert_string.java
new file mode 100644
index 00000000000..7c161205131
--- /dev/null
+++ b/regression/strings/smoke_tests/java_insert_string/test_insert_string.java
@@ -0,0 +1,10 @@
+public class test_insert_string
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder sb = new StringBuilder("ad");
+      sb.insert(1, "bc");
+      String s = sb.toString();
+      assert(s.equals("abcd"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_int_to_string/test.desc b/regression/strings/smoke_tests/java_int_to_string/test.desc
new file mode 100644
index 00000000000..66afed35808
--- /dev/null
+++ b/regression/strings/smoke_tests/java_int_to_string/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_int.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_int_to_string/test_int.class b/regression/strings/smoke_tests/java_int_to_string/test_int.class
new file mode 100644
index 00000000000..eff0e5a422e
Binary files /dev/null and b/regression/strings/smoke_tests/java_int_to_string/test_int.class differ
diff --git a/regression/strings/smoke_tests/java_int_to_string/test_int.java b/regression/strings/smoke_tests/java_int_to_string/test_int.java
new file mode 100644
index 00000000000..f46411ed166
--- /dev/null
+++ b/regression/strings/smoke_tests/java_int_to_string/test_int.java
@@ -0,0 +1,11 @@
+public class test_int
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = Integer.toString(12);
+      assert(s.equals("12"));
+      String t = Integer.toString(-23);
+      System.out.println(t);
+      assert(t.equals("-23"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_intern/test.desc b/regression/strings/smoke_tests/java_intern/test.desc
new file mode 100644
index 00000000000..fead2e1d408
--- /dev/null
+++ b/regression/strings/smoke_tests/java_intern/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_intern.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 9.* SUCCESS$
+--
diff --git a/regression/strings/smoke_tests/java_intern/test_intern.class b/regression/strings/smoke_tests/java_intern/test_intern.class
new file mode 100644
index 00000000000..894615c0a9a
Binary files /dev/null and b/regression/strings/smoke_tests/java_intern/test_intern.class differ
diff --git a/regression/strings/smoke_tests/java_intern/test_intern.java b/regression/strings/smoke_tests/java_intern/test_intern.java
new file mode 100644
index 00000000000..7f9d5283597
--- /dev/null
+++ b/regression/strings/smoke_tests/java_intern/test_intern.java
@@ -0,0 +1,11 @@
+public class test_intern
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s1 = "abc";
+      String s3 = "abc";
+      String x = s1.intern();
+      String y = s3.intern();
+      assert(x == y);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_last_index_of/test.desc b/regression/strings/smoke_tests/java_last_index_of/test.desc
new file mode 100644
index 00000000000..744861fe5a7
--- /dev/null
+++ b/regression/strings/smoke_tests/java_last_index_of/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_last_index_of.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_last_index_of/test_last_index_of.class b/regression/strings/smoke_tests/java_last_index_of/test_last_index_of.class
new file mode 100644
index 00000000000..4455da4d179
Binary files /dev/null and b/regression/strings/smoke_tests/java_last_index_of/test_last_index_of.class differ
diff --git a/regression/strings/smoke_tests/java_last_index_of/test_last_index_of.java b/regression/strings/smoke_tests/java_last_index_of/test_last_index_of.java
new file mode 100644
index 00000000000..8b3a0904d5b
--- /dev/null
+++ b/regression/strings/smoke_tests/java_last_index_of/test_last_index_of.java
@@ -0,0 +1,10 @@
+public class test_last_index_of
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "abcab";
+      String ab = "ab";
+      int i = s.lastIndexOf(ab);
+      assert(i == 3);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_last_index_of_char/test.desc b/regression/strings/smoke_tests/java_last_index_of_char/test.desc
new file mode 100644
index 00000000000..707d804dc4a
--- /dev/null
+++ b/regression/strings/smoke_tests/java_last_index_of_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_last_index_of_char.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_last_index_of_char/test_last_index_of_char.class b/regression/strings/smoke_tests/java_last_index_of_char/test_last_index_of_char.class
new file mode 100644
index 00000000000..388717f4261
Binary files /dev/null and b/regression/strings/smoke_tests/java_last_index_of_char/test_last_index_of_char.class differ
diff --git a/regression/strings/smoke_tests/java_last_index_of_char/test_last_index_of_char.java b/regression/strings/smoke_tests/java_last_index_of_char/test_last_index_of_char.java
new file mode 100644
index 00000000000..029d59c9d68
--- /dev/null
+++ b/regression/strings/smoke_tests/java_last_index_of_char/test_last_index_of_char.java
@@ -0,0 +1,9 @@
+public class test_last_index_of_char
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = "abcab";
+      int n = s.lastIndexOf('a');
+      assert(n == 3);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_length/test.desc b/regression/strings/smoke_tests/java_length/test.desc
new file mode 100644
index 00000000000..dd19ec73e6b
--- /dev/null
+++ b/regression/strings/smoke_tests/java_length/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_length.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_length/test_length.class b/regression/strings/smoke_tests/java_length/test_length.class
new file mode 100644
index 00000000000..9273d09869b
Binary files /dev/null and b/regression/strings/smoke_tests/java_length/test_length.class differ
diff --git a/regression/strings/smoke_tests/java_length/test_length.java b/regression/strings/smoke_tests/java_length/test_length.java
new file mode 100644
index 00000000000..4222414fa80
--- /dev/null
+++ b/regression/strings/smoke_tests/java_length/test_length.java
@@ -0,0 +1,9 @@
+public class test_length
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abc");
+      int l = s.length();
+      assert(l == 3);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_parseint/test.desc b/regression/strings/smoke_tests/java_parseint/test.desc
new file mode 100644
index 00000000000..00726803b43
--- /dev/null
+++ b/regression/strings/smoke_tests/java_parseint/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_parseint.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 7.* SUCCESS$
+^\[.*assertion.2\].* line 8.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_parseint/test_parseint.class b/regression/strings/smoke_tests/java_parseint/test_parseint.class
new file mode 100644
index 00000000000..e1ffe0c7210
Binary files /dev/null and b/regression/strings/smoke_tests/java_parseint/test_parseint.class differ
diff --git a/regression/strings/smoke_tests/java_parseint/test_parseint.java b/regression/strings/smoke_tests/java_parseint/test_parseint.java
new file mode 100644
index 00000000000..f278f273675
--- /dev/null
+++ b/regression/strings/smoke_tests/java_parseint/test_parseint.java
@@ -0,0 +1,10 @@
+public class test_parseint
+{
+   public static void main(String[] argv)
+   {
+      String twelve = new String("12");
+      int parsed = Integer.parseInt(twelve);
+      assert(parsed == 12);
+      assert(parsed != 12);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_replace/test.desc b/regression/strings/smoke_tests/java_replace/test.desc
new file mode 100644
index 00000000000..e26eda70fc0
--- /dev/null
+++ b/regression/strings/smoke_tests/java_replace/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_replace.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_replace/test_replace.class b/regression/strings/smoke_tests/java_replace/test_replace.class
new file mode 100644
index 00000000000..d15509ee8ac
Binary files /dev/null and b/regression/strings/smoke_tests/java_replace/test_replace.class differ
diff --git a/regression/strings/smoke_tests/java_replace/test_replace.java b/regression/strings/smoke_tests/java_replace/test_replace.java
new file mode 100644
index 00000000000..07e7ac036b9
--- /dev/null
+++ b/regression/strings/smoke_tests/java_replace/test_replace.java
@@ -0,0 +1,13 @@
+public class test_replace
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("abcabd");
+      String u = s.replace("d","z");
+      System.out.println(u);
+      assert(u.equals("abcabz"));
+      String v = u.replace("ab","w");
+      System.out.println(v);
+      assert(v.equals("wcwz"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_replace_char/test.desc b/regression/strings/smoke_tests/java_replace_char/test.desc
new file mode 100644
index 00000000000..376013e006e
--- /dev/null
+++ b/regression/strings/smoke_tests/java_replace_char/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_replace_char.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_replace_char/test_replace_char.class b/regression/strings/smoke_tests/java_replace_char/test_replace_char.class
new file mode 100644
index 00000000000..64626b3b09d
Binary files /dev/null and b/regression/strings/smoke_tests/java_replace_char/test_replace_char.class differ
diff --git a/regression/strings/smoke_tests/java_replace_char/test_replace_char.java b/regression/strings/smoke_tests/java_replace_char/test_replace_char.java
new file mode 100644
index 00000000000..82a023924e2
--- /dev/null
+++ b/regression/strings/smoke_tests/java_replace_char/test_replace_char.java
@@ -0,0 +1,9 @@
+public class test_replace_char
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("abcabd");
+      String t = s.replace('b','m');
+      assert(t.equals("amcamd"));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_set_char_at/test.desc b/regression/strings/smoke_tests/java_set_char_at/test.desc
new file mode 100644
index 00000000000..dea9f3f84e3
--- /dev/null
+++ b/regression/strings/smoke_tests/java_set_char_at/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_set_char_at.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_set_char_at/test_set_char_at.class b/regression/strings/smoke_tests/java_set_char_at/test_set_char_at.class
new file mode 100644
index 00000000000..6e843afbe2a
Binary files /dev/null and b/regression/strings/smoke_tests/java_set_char_at/test_set_char_at.class differ
diff --git a/regression/strings/smoke_tests/java_set_char_at/test_set_char_at.java b/regression/strings/smoke_tests/java_set_char_at/test_set_char_at.java
new file mode 100644
index 00000000000..fd1d1fbf9e2
--- /dev/null
+++ b/regression/strings/smoke_tests/java_set_char_at/test_set_char_at.java
@@ -0,0 +1,13 @@
+public class test_set_char_at
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abc");
+      char c = s.charAt(1);
+      StringBuilder sb = new StringBuilder(s);
+      sb.setCharAt(1,'w');
+      s = sb.toString();
+      assert(s.equals("Awc"));
+      assert(s.charAt(2)=='c');
+   }
+}
diff --git a/regression/strings/smoke_tests/java_set_length/test.desc b/regression/strings/smoke_tests/java_set_length/test.desc
new file mode 100644
index 00000000000..70dd8c9c073
--- /dev/null
+++ b/regression/strings/smoke_tests/java_set_length/test.desc
@@ -0,0 +1,9 @@
+FUTURE
+test_set_length.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* SUCCESS$
+^\[.*assertion.2\].* line 9.* SUCCESS$
+^\[.*assertion.3\].* line 10.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_set_length/test_set_length.class b/regression/strings/smoke_tests/java_set_length/test_set_length.class
new file mode 100644
index 00000000000..8cb9e416191
Binary files /dev/null and b/regression/strings/smoke_tests/java_set_length/test_set_length.class differ
diff --git a/regression/strings/smoke_tests/java_set_length/test_set_length.java b/regression/strings/smoke_tests/java_set_length/test_set_length.java
new file mode 100644
index 00000000000..5894b27beeb
--- /dev/null
+++ b/regression/strings/smoke_tests/java_set_length/test_set_length.java
@@ -0,0 +1,12 @@
+public class test_set_length
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder s = new StringBuilder("abc");
+      s.setLength(10);
+      String t = s.toString();
+      assert(t.startsWith("abc"));
+      assert(t.length() == 10);
+      assert(t.length() == 3);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_starts_with/test.desc b/regression/strings/smoke_tests/java_starts_with/test.desc
new file mode 100644
index 00000000000..8f099a2841e
--- /dev/null
+++ b/regression/strings/smoke_tests/java_starts_with/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_starts_with.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* SUCCESS$
+^\[.*assertion.2\].* line 9.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_starts_with/test_starts_with.class b/regression/strings/smoke_tests/java_starts_with/test_starts_with.class
new file mode 100644
index 00000000000..da1decd8d35
Binary files /dev/null and b/regression/strings/smoke_tests/java_starts_with/test_starts_with.class differ
diff --git a/regression/strings/smoke_tests/java_starts_with/test_starts_with.java b/regression/strings/smoke_tests/java_starts_with/test_starts_with.java
new file mode 100644
index 00000000000..aba79d846c0
--- /dev/null
+++ b/regression/strings/smoke_tests/java_starts_with/test_starts_with.java
@@ -0,0 +1,11 @@
+public class test_starts_with
+{
+   public static void main(/*String[] argv*/)
+   {
+      String s = new String("Abcd");
+      String pref = "Ab";
+      String bad_pref = "bc";
+      assert(s.startsWith(pref));
+      assert(s.startsWith(bad_pref));
+   }
+}
diff --git a/regression/strings/smoke_tests/java_string_builder_length/test.desc b/regression/strings/smoke_tests/java_string_builder_length/test.desc
new file mode 100644
index 00000000000..c52a492c90c
--- /dev/null
+++ b/regression/strings/smoke_tests/java_string_builder_length/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_sb_length.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_string_builder_length/test_sb_length.class b/regression/strings/smoke_tests/java_string_builder_length/test_sb_length.class
new file mode 100644
index 00000000000..cfc35874d26
Binary files /dev/null and b/regression/strings/smoke_tests/java_string_builder_length/test_sb_length.class differ
diff --git a/regression/strings/smoke_tests/java_string_builder_length/test_sb_length.java b/regression/strings/smoke_tests/java_string_builder_length/test_sb_length.java
new file mode 100644
index 00000000000..b616749ffb4
--- /dev/null
+++ b/regression/strings/smoke_tests/java_string_builder_length/test_sb_length.java
@@ -0,0 +1,9 @@
+public class test_sb_length
+{
+   public static void main(/*String[] argv*/)
+   {
+      StringBuilder x = new StringBuilder("abc");
+      x.append("de");
+      assert(x.length() == 5);
+   }
+}
diff --git a/regression/strings/smoke_tests/java_subsequence/test.desc b/regression/strings/smoke_tests/java_subsequence/test.desc
new file mode 100644
index 00000000000..8ce502d7b11
--- /dev/null
+++ b/regression/strings/smoke_tests/java_subsequence/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_subsequence.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_subsequence/test_subsequence.class b/regression/strings/smoke_tests/java_subsequence/test_subsequence.class
new file mode 100644
index 00000000000..0f8410939e1
Binary files /dev/null and b/regression/strings/smoke_tests/java_subsequence/test_subsequence.class differ
diff --git a/regression/strings/smoke_tests/java_subsequence/test_subsequence.java b/regression/strings/smoke_tests/java_subsequence/test_subsequence.java
new file mode 100644
index 00000000000..4d8d79cb381
--- /dev/null
+++ b/regression/strings/smoke_tests/java_subsequence/test_subsequence.java
@@ -0,0 +1,14 @@
+public class test_subsequence
+{
+   public static void main(/*String[] argv*/)
+   {
+      String abcdef = "AbcDef";
+      CharSequence cde = abcdef.subSequence(2,5);
+      char c = cde.charAt(0);
+      char d = cde.charAt(1);
+      char e = cde.charAt(2);
+      assert(c == 'c');
+      assert(d == 'D');
+      assert(e == 'e');
+  }
+}
diff --git a/regression/strings/smoke_tests/java_substring/test.desc b/regression/strings/smoke_tests/java_substring/test.desc
new file mode 100644
index 00000000000..52073b4334f
--- /dev/null
+++ b/regression/strings/smoke_tests/java_substring/test.desc
@@ -0,0 +1,7 @@
+FUTURE
+test_substring.class
+--string-refine
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
diff --git a/regression/strings/smoke_tests/java_substring/test_substring.class b/regression/strings/smoke_tests/java_substring/test_substring.class
new file mode 100644
index 00000000000..3ba0b60e7f2
Binary files /dev/null and b/regression/strings/smoke_tests/java_substring/test_substring.class differ
diff --git a/regression/strings/smoke_tests/java_substring/test_substring.java b/regression/strings/smoke_tests/java_substring/test_substring.java
new file mode 100644
index 00000000000..03a33fdbebd
--- /dev/null
+++ b/regression/strings/smoke_tests/java_substring/test_substring.java
@@ -0,0 +1,14 @@
+public class test_substring
+{
+   public static void main(/*String[] argv*/)
+   {
+      String abcdef = "AbcDef";
+      String cde = abcdef.substring(2,5);
+      char c = cde.charAt(0);
+      char d = cde.charAt(1);
+      char e = cde.charAt(2);
+      assert(c == 'c');
+      assert(d == 'D');
+      assert(e == 'e');
+   }
+}
diff --git a/regression/strings/smoke_tests/java_trim/test.desc b/regression/strings/smoke_tests/java_trim/test.desc
new file mode 100644
index 00000000000..1d25121cbbc
--- /dev/null
+++ b/regression/strings/smoke_tests/java_trim/test.desc
@@ -0,0 +1,8 @@
+FUTURE
+test_trim.class
+--string-refine
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 6.* SUCCESS$
+^\[.*assertion.2\].* line 7.* FAILURE$
+--
diff --git a/regression/strings/smoke_tests/java_trim/test_trim.class b/regression/strings/smoke_tests/java_trim/test_trim.class
new file mode 100644
index 00000000000..33b34714ae2
Binary files /dev/null and b/regression/strings/smoke_tests/java_trim/test_trim.class differ
diff --git a/regression/strings/smoke_tests/java_trim/test_trim.java b/regression/strings/smoke_tests/java_trim/test_trim.java
new file mode 100644
index 00000000000..20dd7ba2796
--- /dev/null
+++ b/regression/strings/smoke_tests/java_trim/test_trim.java
@@ -0,0 +1,9 @@
+public class test_trim
+{
+   public static void main(/*String[] argv*/)
+   {
+      String empty = "   ";
+      assert(empty.trim().isEmpty());
+      assert(empty.isEmpty());
+   }
+}
diff --git a/regression/strings/test3.4/test.desc b/regression/strings/test3.4/test.desc
index d88e1c83744..94d8faa7afc 100644
--- a/regression/strings/test3.4/test.desc
+++ b/regression/strings/test3.4/test.desc
@@ -1,7 +1,7 @@
 FUTURE
-test.c
+test_init.class
 --string-refine
-^EXIT=10$
+^EXIT=0$
 ^SIGNAL=0$
-^VERIFICATION FAILED$
+^VERIFICATION SUCCESSFUL$
 --
diff --git a/regression/strings/test_char_set/test.desc b/regression/strings/test_char_set/test.desc
index 99f3cfd81de..c9516dd694a 100644
--- a/regression/strings/test_char_set/test.desc
+++ b/regression/strings/test_char_set/test.desc
@@ -3,6 +3,6 @@ test.c
 --string-refine
 ^EXIT=10$
 ^SIGNAL=0$
-^\[main.assertion.1\] assertion __CPROVER_string_equal\(t, __CPROVER_string_literal\("apc"\)): SUCCESS$
-^\[main.assertion.2\] assertion __CPROVER_string_equal\(t, __CPROVER_string_literal\("abc"\)): FAILURE$
+^\[.*assertion.1\].* SUCCESS$
+^\[.*assertion.2\].* FAILURE$
 --
diff --git a/regression/strings/test_equal/test.desc b/regression/strings/test_equal/test.desc
index 5fbe05f8fdd..34906b377a0 100644
--- a/regression/strings/test_equal/test.desc
+++ b/regression/strings/test_equal/test.desc
@@ -3,6 +3,6 @@ test.c
 --string-refine
 ^EXIT=10$
 ^SIGNAL=0$
-^\[main.assertion.1\] assertion __CPROVER_string_equal\(s, __CPROVER_string_literal\("pippo"\)): SUCCESS$
-^\[main.assertion.2\] assertion __CPROVER_string_equal\(s, __CPROVER_string_literal\("mippo"\)): FAILURE$
+^\[.*.assertion.1\].* SUCCESS$
+^\[.*.assertion.2\].* FAILURE$
 --
diff --git a/regression/strings/test_substring/test.desc b/regression/strings/test_substring/test.desc
index a32376aca23..c600dbf19e6 100644
--- a/regression/strings/test_substring/test.desc
+++ b/regression/strings/test_substring/test.desc
@@ -3,8 +3,8 @@ test.c
 --string-refine
 ^EXIT=10$
 ^SIGNAL=0$
-^\[main.assertion.1\] assertion __CPROVER_string_equal\(t,__CPROVER_string_literal\("cd"\)): SUCCESS$
-^\[main.assertion.2\] assertion __CPROVER_string_equal\(t,__CPROVER_string_literal\("cc"\)): FAILURE$
-^\[main.assertion.3\] assertion !__CPROVER_string_equal\(t,__CPROVER_string_literal\("bc"\)): SUCCESS$
-^\[main.assertion.4\] assertion !__CPROVER_string_equal\(t,__CPROVER_string_literal\("cd"\)): FAILURE$
+^\[.*assertion.1\].* SUCCESS$
+^\[.*assertion.2\].* FAILURE$
+^\[.*assertion.3\].* SUCCESS$
+^\[.*assertion.4\].* FAILURE$
 --
diff --git a/src/cbmc/cbmc_parse_options.cpp b/src/cbmc/cbmc_parse_options.cpp
index e33e700e0ca..a910614844c 100644
--- a/src/cbmc/cbmc_parse_options.cpp
+++ b/src/cbmc/cbmc_parse_options.cpp
@@ -20,6 +20,7 @@ Author: Daniel Kroening, kroening@kroening.com
 #include <ansi-c/c_preprocess.h>
 
 #include <goto-programs/goto_convert_functions.h>
+#include <goto-programs/string_refine_preprocess.h>
 #include <goto-programs/remove_function_pointers.h>
 #include <goto-programs/remove_virtual_functions.h>
 #include <goto-programs/remove_instanceof.h>
@@ -310,6 +311,17 @@ void cbmc_parse_optionst::get_command_line_options(optionst &options)
     options.set_option("refine-arithmetic", true);
   }
 
+
+  if(cmdline.isset("string-refine"))
+  {
+    options.set_option("string-refine", true);
+    options.set_option("string-non-empty", cmdline.isset("string-non-empty"));
+    options.set_option("string-printable", cmdline.isset("string-printable"));
+    if(cmdline.isset("string-max-length"))
+      options.set_option(
+        "string-max-length", cmdline.get_value("string-max-length"));
+  }
+
   if(cmdline.isset("max-node-refinement"))
     options.set_option(
       "max-node-refinement",
@@ -904,6 +916,14 @@ bool cbmc_parse_optionst::process_goto_program(
     status() << "Partial Inlining" << eom;
     goto_partial_inline(goto_functions, ns, ui_message_handler);
 
+
+    if(cmdline.isset("string-refine"))
+    {
+      status() << "Preprocessing for string refinement" << eom;
+      string_refine_preprocesst(
+        symbol_table, goto_functions, ui_message_handler);
+    }
+
     // remove returns, gcc vectors, complex
     remove_returns(symbol_table, goto_functions);
     remove_vector(symbol_table, goto_functions);
@@ -1191,6 +1211,10 @@ void cbmc_parse_optionst::help()
     " --yices                      use Yices\n"
     " --z3                         use Z3\n"
     " --refine                     use refinement procedure (experimental)\n"
+    " --string-refine              use string refinement (experimental)\n"
+    " --string-non-empty           add constraint that strings are non empty (experimental)\n" // NOLINT(*)
+    " --string-printable           add constraint that strings are printable (experimental)\n" // NOLINT(*)
+    " --string-max-length          add constraint on the length of strings (experimental)\n" // NOLINT(*)
     " --outfile filename           output formula to given file\n"
     " --arrays-uf-never            never turn arrays into uninterpreted functions\n" // NOLINT(*)
     " --arrays-uf-always           always turn arrays into uninterpreted functions\n" // NOLINT(*)
diff --git a/src/cbmc/cbmc_parse_options.h b/src/cbmc/cbmc_parse_options.h
index a3fc5e7e7d3..e2ce96ba43f 100644
--- a/src/cbmc/cbmc_parse_options.h
+++ b/src/cbmc/cbmc_parse_options.h
@@ -37,6 +37,7 @@ class optionst;
   "(no-sat-preprocessor)" \
   "(no-pretty-names)(beautify)" \
   "(dimacs)(refine)(max-node-refinement):(refine-arrays)(refine-arithmetic)"\
+  "(string-refine)(string-non-empty)(string-printable)(string-max-length):" \
   "(aig)(16)(32)(64)(LP64)(ILP64)(LLP64)(ILP32)(LP32)" \
   "(little-endian)(big-endian)" \
   "(show-goto-functions)(show-loops)" \
diff --git a/src/cbmc/cbmc_solvers.cpp b/src/cbmc/cbmc_solvers.cpp
index ccd660dc586..dace046cc17 100644
--- a/src/cbmc/cbmc_solvers.cpp
+++ b/src/cbmc/cbmc_solvers.cpp
@@ -14,6 +14,7 @@ Author: Daniel Kroening, kroening@kroening.com
 
 #include <solvers/sat/satcheck.h>
 #include <solvers/refinement/bv_refinement.h>
+#include <solvers/refinement/string_refinement.h>
 #include <solvers/smt1/smt1_dec.h>
 #include <solvers/smt2/smt2_dec.h>
 #include <solvers/cvc/cvc_dec.h>
@@ -213,6 +214,39 @@ cbmc_solverst::solvert* cbmc_solverst::get_bv_refinement()
 
 /*******************************************************************\
 
+Function: cbmc_solverst::get_string_refinement
+
+ Outputs: a solver for cbmc
+
+ Purpose: the string refinement adds to the bit vector refinement
+          specifications for functions from the Java string library
+
+\*******************************************************************/
+
+cbmc_solverst::solvert* cbmc_solverst::get_string_refinement()
+{
+  propt *prop;
+  prop=new satcheck_no_simplifiert();
+  prop->set_message_handler(get_message_handler());
+
+  string_refinementt *string_refinement=new string_refinementt(
+    ns, *prop, MAX_NB_REFINEMENT);
+  string_refinement->set_ui(ui);
+
+  string_refinement->do_concretizing=options.get_bool_option("trace");
+  if(options.get_bool_option("string-max-length"))
+    string_refinement->set_max_string_length(
+      options.get_signed_int_option("string-max-length"));
+  if(options.get_bool_option("string-non-empty"))
+    string_refinement->enforce_non_empty_string();
+  if(options.get_bool_option("string-printable"))
+    string_refinement->enforce_printable_characters();
+
+  return new solvert(string_refinement, prop);
+}
+
+/*******************************************************************\
+
 Function: cbmc_solverst::get_smt1
 
   Inputs:
diff --git a/src/cbmc/cbmc_solvers.h b/src/cbmc/cbmc_solvers.h
index 42d47fcaed3..be4a0e0ccde 100644
--- a/src/cbmc/cbmc_solvers.h
+++ b/src/cbmc/cbmc_solvers.h
@@ -111,15 +111,17 @@ class cbmc_solverst:public messaget
     solvert *solver;
 
     if(options.get_bool_option("dimacs"))
-      solver = get_dimacs();
+      solver=get_dimacs();
     else if(options.get_bool_option("refine"))
-      solver = get_bv_refinement();
+      solver=get_bv_refinement();
+    else if(options.get_bool_option("string-refine"))
+      solver=get_string_refinement();
     else if(options.get_bool_option("smt1"))
-      solver = get_smt1(get_smt1_solver_type());
+      solver=get_smt1(get_smt1_solver_type());
     else if(options.get_bool_option("smt2"))
-      solver = get_smt2(get_smt2_solver_type());
+      solver=get_smt2(get_smt2_solver_type());
     else
-      solver = get_default();
+      solver=get_default();
 
     return std::unique_ptr<solvert>(solver);
   }
@@ -141,6 +143,7 @@ class cbmc_solverst:public messaget
   solvert *get_default();
   solvert *get_dimacs();
   solvert *get_bv_refinement();
+  solvert *get_string_refinement();
   solvert *get_smt1(smt1_dect::solvert solver);
   solvert *get_smt2(smt2_dect::solvert solver);
 
diff --git a/src/goto-programs/Makefile b/src/goto-programs/Makefile
index d5cc5ea25eb..f23a0e387ed 100644
--- a/src/goto-programs/Makefile
+++ b/src/goto-programs/Makefile
@@ -20,7 +20,8 @@ SRC = goto_convert.cpp goto_convert_function_call.cpp \
       slice_global_inits.cpp goto_inline_class.cpp class_identifier.cpp \
       show_goto_functions_json.cpp \
       show_goto_functions_xml.cpp \
-      remove_static_init_loops.cpp remove_instanceof.cpp
+      remove_static_init_loops.cpp remove_instanceof.cpp \
+      string_refine_preprocess.cpp
 
 INCLUDES= -I ..
 
diff --git a/src/goto-programs/string_refine_preprocess.cpp b/src/goto-programs/string_refine_preprocess.cpp
new file mode 100644
index 00000000000..bf7a0083902
--- /dev/null
+++ b/src/goto-programs/string_refine_preprocess.cpp
@@ -0,0 +1,1401 @@
+/*******************************************************************\
+
+Module: Preprocess a goto-programs so that calls to the java String
+        library are recognized by the string solver
+
+Author: Romain Brenguier
+
+Date:   September 2016
+
+\*******************************************************************/
+
+#include <util/std_expr.h>
+#include <util/symbol_table.h>
+#include <util/pointer_offset_size.h>
+#include <util/prefix.h>
+#include <util/string_expr.h>
+#include <util/refined_string_type.h>
+#include <goto-programs/class_identifier.h>
+#include <java_bytecode/java_types.h>
+
+#include "string_refine_preprocess.h"
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::check_java_type
+
+  Inputs: a type and a string
+
+ Outputs: Boolean telling whether the type is a struct with the given
+          tag or a symbolic type with the tag prefixed by "java::"
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::check_java_type(
+  const typet &type, const std::string &tag)
+{
+  if(type.id()==ID_symbol)
+  {
+    irep_idt tag_id=to_symbol_type(type).get_identifier();
+    return tag_id=="java::"+tag;
+  }
+  else if(type.id()==ID_struct)
+  {
+    irep_idt tag_id=to_struct_type(type).get_tag();
+    return tag_id==tag;
+  }
+  return false;
+}
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_string_pointer_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of java string pointers
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_string_pointer_type(const typet &type)
+{
+  if(type.id()==ID_pointer)
+  {
+    const pointer_typet &pt=to_pointer_type(type);
+    const typet &subtype=pt.subtype();
+    return is_java_string_type(subtype);
+  }
+  return false;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_string_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of java string
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_string_type(const typet &type)
+{
+  return check_java_type(type, "java.lang.String");
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_string_builder_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of java string builder
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_string_builder_type(const typet &type)
+{
+  return check_java_type(type, "java.lang.StringBuilder");
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_string_builder_pointer_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of java StringBuilder
+          pointers
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_string_builder_pointer_type(
+  const typet &type)
+{
+  if(type.id()==ID_pointer)
+  {
+    const pointer_typet &pt=to_pointer_type(type);
+    const typet &subtype=pt.subtype();
+    return is_java_string_builder_type(subtype);
+  }
+  return false;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_char_sequence_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of java char sequence
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_char_sequence_type(const typet &type)
+{
+  return check_java_type(type, "java.lang.CharSequence");
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_char_sequence_pointer_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of a pointer
+          to a java char sequence
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_char_sequence_pointer_type(
+  const typet &type)
+{
+  if(type.id()==ID_pointer)
+  {
+    const pointer_typet &pt=to_pointer_type(type);
+    const typet &subtype=pt.subtype();
+    return is_java_char_sequence_type(subtype);
+  }
+  return false;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_char_array_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of java char array
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_char_array_type(const typet &type)
+{
+  return check_java_type(type, "array[char]");
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::is_java_char_array_pointer_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the type is that of a pointer
+          to a java char array
+
+\*******************************************************************/
+
+bool string_refine_preprocesst::is_java_char_array_pointer_type(
+  const typet &type)
+{
+  if(type.id()==ID_pointer)
+  {
+    const pointer_typet &pt=to_pointer_type(type);
+    const typet &subtype=pt.subtype();
+    return is_java_char_array_type(subtype);
+  }
+  return false;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::new_tmp_symbol
+
+  Inputs: a name and a type
+
+ Outputs: a new symbol
+
+ Purpose: add a temporary symbol with the given name and type to the
+          symbol table and returns it
+
+\*******************************************************************/
+
+symbol_exprt string_refine_preprocesst::new_tmp_symbol(
+  const std::string &prefix, const typet &type)
+{
+  // TODO : this method should be replaced by a call to get_fresh_aux_symbol
+  // once fresh symbol generation has been factored out
+  auxiliary_symbolt tmp_symbol;
+  std::ostringstream buf;
+  buf << "string_preprocess_tmp" << (next_symbol_id++) << "$" << prefix;
+  std::string name=buf.str();
+  tmp_symbol.base_name=name;
+  tmp_symbol.is_static_lifetime=false;
+  tmp_symbol.mode=ID_java;
+  tmp_symbol.name=name;
+  tmp_symbol.type=type;
+  symbol_table.add(tmp_symbol);
+  return tmp_symbol.symbol_expr();
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::new_symbol
+
+  Inputs: a name and a type
+
+ Outputs: a new symbol
+
+ Purpose: add a symbol with the given name and type to the symbol table
+          and returns it
+
+\*******************************************************************/
+
+symbol_exprt string_refine_preprocesst::new_symbol(
+  const std::string &prefix, const typet &type, bool static_lifetime)
+{
+  symbolt tmp_symbol;
+  std::ostringstream buf;
+  buf << "string_preprocess" << (next_symbol_id++) << "$" << prefix;
+  std::string name=buf.str();
+  tmp_symbol.base_name=name;
+  tmp_symbol.is_static_lifetime=static_lifetime;
+  tmp_symbol.is_state_var=static_lifetime;
+  tmp_symbol.is_type=false;
+  tmp_symbol.is_lvalue=true;
+  tmp_symbol.mode=ID_java;
+  tmp_symbol.name=name;
+  tmp_symbol.type=type;
+  symbol_table.add(tmp_symbol);
+  return tmp_symbol.symbol_expr();
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::declare_function
+
+  Inputs: a name and a type
+
+ Purpose: declare a function with the given name and type
+
+\*******************************************************************/
+
+void string_refine_preprocesst::declare_function(
+  irep_idt function_name, const typet &type)
+{
+  auxiliary_symbolt func_symbol;
+  func_symbol.base_name=function_name;
+  func_symbol.is_static_lifetime=false;
+  func_symbol.mode=ID_java;
+  func_symbol.name=function_name;
+  func_symbol.type=type;
+  symbol_table.add(func_symbol);
+  goto_functions.function_map[function_name];
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::get_data_and_length_type_of_char_array
+
+  Inputs: an expression, a reference to a data type and a reference to a
+          length type
+
+ Purpose: assuming the expression is a char array, figure out what
+          the types for length and data are and put them into the references
+          given as argument
+
+\*******************************************************************/
+
+void string_refine_preprocesst::get_data_and_length_type_of_char_array(
+  const exprt &expr, typet &data_type, typet &length_type)
+{
+  typet object_type=ns.follow(expr.type());
+  assert(object_type.id()==ID_struct);
+  const struct_typet &struct_type=to_struct_type(object_type);
+  for(auto component : struct_type.components())
+    if(component.get_name()=="length")
+      length_type=component.type();
+    else if(component.get_name()=="data")
+      data_type=component.type();
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::get_data_and_length_type_of_string
+
+  Inputs: an expression, a reference to a data type and a reference to a
+          length type
+
+ Purpose: assuming the expression is a java string, figure out what
+          the types for length and data are and put them into the references
+          given as argument
+
+\*******************************************************************/
+
+void string_refine_preprocesst::get_data_and_length_type_of_string(
+  const exprt &expr, typet &data_type, typet &length_type)
+{
+  assert(is_java_string_type(expr.type()) ||
+         is_java_string_builder_type(expr.type()) ||
+         is_java_char_sequence_type(expr.type()));
+  typet object_type=ns.follow(expr.type());
+  const struct_typet &struct_type=to_struct_type(object_type);
+  for(const auto &component : struct_type.components())
+    if(component.get_name()=="length")
+      length_type=component.type();
+    else if(component.get_name()=="data")
+      data_type=component.type();
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_cprover_string_assign
+
+  Inputs: a goto_program, a position in this program, an expression and a
+          location
+
+ Outputs: an expression
+
+ Purpose: Introduce a temporary variable for cprover strings;
+          returns the cprover_string corresponding to rhs if it is a string
+          pointer and the original rhs otherwise.
+
+\*******************************************************************/
+
+exprt string_refine_preprocesst::make_cprover_string_assign(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const exprt &rhs,
+  const source_locationt &location)
+{
+  if(implements_java_char_sequence(rhs.type()))
+  {
+    // We do the following assignments:
+    // 1 cprover_string_length= *(rhs->length)
+    // 2 cprover_string_array = *(rhs->data)
+    // 3 cprover_string = { cprover_string_length; cprover_string_array }
+
+    dereference_exprt deref(rhs, rhs.type().subtype());
+    typet data_type, length_type;
+    get_data_and_length_type_of_string(deref, data_type, length_type);
+    std::list<code_assignt> assignments;
+
+    // 1) cprover_string_length= *(rhs->length)
+    symbol_exprt length_lhs=new_symbol(
+      "cprover_string_length", length_type);
+
+    member_exprt deref_length(deref, "length", length_type);
+    assignments.emplace_back(length_lhs, deref_length);
+
+    // 2) cprover_string_array = *(rhs->data)
+    symbol_exprt array_lhs=new_symbol(
+      "cprover_string_array", data_type.subtype());
+    member_exprt data(deref, "data", data_type);
+    dereference_exprt deref_data(data, data_type.subtype());
+    assignments.emplace_back(array_lhs, deref_data);
+
+    // 3) cprover_string = { cprover_string_length; cprover_string_array }
+    // This assignment is useful for finding witnessing strings for counter
+    // examples
+    refined_string_typet ref_type(length_type, java_char_type());
+    string_exprt new_rhs(length_lhs, array_lhs, ref_type);
+
+    symbol_exprt lhs=new_symbol("cprover_string", new_rhs.type());
+    assignments.emplace_back(lhs, new_rhs);
+
+    insert_assignments(
+      goto_program, target, target->function, location, assignments);
+    target=goto_program.insert_after(target);
+    return new_rhs;
+  }
+  else if(rhs.id()==ID_typecast &&
+          implements_java_char_sequence(rhs.op0().type()))
+  {
+    exprt new_rhs=make_cprover_string_assign(
+      goto_program, target, rhs.op0(), location);
+    return typecast_exprt(new_rhs, rhs.type());
+  }
+  else
+    return rhs;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_cprover_char_array_assign
+
+  Inputs: a goto_program, a position in this program, an expression of
+          type char array pointer and a location
+
+ Outputs: a string expression
+
+ Purpose: Introduce a temporary variable for cprover strings;
+          returns the cprover_string corresponding to rhs
+
+\*******************************************************************/
+
+string_exprt string_refine_preprocesst::make_cprover_char_array_assign(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const exprt &rhs,
+  const source_locationt &location)
+{
+  assert(is_java_char_array_pointer_type(rhs.type()));
+
+  // We do the following assignments:
+  // deref=*(rhs->data)
+  // array= typecast(&deref);
+  // string={ rhs->length; array }
+
+  dereference_exprt deref(rhs, rhs.type().subtype());
+  typet length_type, data_type;
+  get_data_and_length_type_of_char_array(deref, data_type, length_type);
+  assert(data_type.id()==ID_pointer);
+  typet char_type=to_pointer_type(data_type).subtype();
+
+  refined_string_typet ref_type(length_type, java_char_type());
+  typet content_type=ref_type.get_content_type();
+  std::list<code_assignt> assignments;
+
+  // deref=*(rhs->data)
+  member_exprt array_rhs(deref, "data", data_type);
+  dereference_exprt deref_array(array_rhs, data_type.subtype());
+  symbol_exprt lhs_deref=new_symbol("char_array_assign$deref",
+                                    data_type.subtype());
+  assignments.emplace_back(lhs_deref, deref_array);
+
+  // array=convert_pointer_to_char_array(*rhs->data)
+  declare_function(ID_cprover_string_array_of_char_pointer_func, content_type);
+  function_application_exprt fun_app(symbol_exprt(
+    ID_cprover_string_array_of_char_pointer_func), content_type);
+  fun_app.arguments().push_back(deref_array);
+  symbol_exprt array=new_symbol("char_array_assign$array", content_type);
+  assignments.emplace_back(array, fun_app);
+
+  // string={ rhs->length; string_array }
+  string_exprt new_rhs(get_length(deref, length_type), array, ref_type);
+  symbol_exprt lhs=new_symbol("char_array_assign$string", ref_type);
+  assignments.emplace_back(lhs, new_rhs);
+
+  insert_assignments(
+    goto_program, target, target->function, location, assignments);
+  target=goto_program.insert_after(target);
+  return new_rhs;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_normal_assign
+
+  Inputs: a goto_program, a position in this program, an expression lhs,
+          a function type, a function name, a vector of arguments, a location
+          and a signature
+
+ Purpose: replace the current instruction by:
+          > lhs=function_name(arguments) : return_type @ location
+          If given, signature can force String conversion of given arguments.
+          The convention for signature is one character by argument
+          and 'S' denotes string.
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_normal_assign(
+  goto_programt &goto_program,
+  goto_programt::targett target,
+  const exprt &lhs,
+  const code_typet &function_type,
+  const irep_idt &function_name,
+  const exprt::operandst &arguments,
+  const source_locationt &location,
+  const std::string &signature)
+{
+  function_application_exprt rhs(
+    symbol_exprt(function_name), function_type.return_type());
+  rhs.add_source_location()=location;
+  declare_function(function_name, function_type);
+
+  exprt::operandst processed_arguments=process_arguments(
+    goto_program, target, arguments, location, signature);
+  rhs.arguments()=processed_arguments;
+
+  code_assignt assignment(lhs, rhs);
+  assignment.add_source_location()=location;
+  target->make_assignment();
+  target->code=assignment;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::insert_assignments
+
+  Inputs: a goto_program, a position in this program, a list of assignments
+
+ Purpose: add the assignments to the program in the order they are given
+
+\*******************************************************************/
+
+void string_refine_preprocesst::insert_assignments(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  irep_idt function,
+  source_locationt location,
+  const std::list<code_assignt> &va)
+{
+  if(va.empty())
+    return;
+
+  auto i=va.begin();
+  target->make_assignment();
+  target->code=*i;
+  target->function=function;
+  target->source_location=location;
+  for(i++; i!=va.end(); i++)
+  {
+    target=goto_program.insert_after(target);
+    target->make_assignment();
+    target->code=*i;
+    target->function=function;
+    target->source_location=location;
+  }
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_string_assign
+
+  Inputs: a goto_program, a position in this program, an expression lhs,
+          a function type, a function name, a vector of arguments, a location
+          and a signature
+
+ Purpose: replace the current instruction by:
+          > lhs=malloc(String *)
+          > lhs->length=function_name_length(arguments)
+          > tmp_data=function_name_data(arguments)
+          > lhs->data=&tmp_data
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_string_assign(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const exprt &lhs,
+  const code_typet &function_type,
+  const irep_idt &function_name,
+  const exprt::operandst &arguments,
+  const source_locationt &location,
+  const std::string &signature)
+{
+  assert(implements_java_char_sequence(function_type.return_type()));
+  dereference_exprt deref(lhs, lhs.type().subtype());
+  typet object_type=ns.follow(deref.type());
+  exprt object_size=size_of_expr(object_type, ns);
+  typet length_type, data_type;
+  get_data_and_length_type_of_string(deref, data_type, length_type);
+
+  std::string fnamel=id2string(function_name)+"_length";
+  std::string fnamed=id2string(function_name)+"_data";
+  declare_function(fnamel, length_type);
+  declare_function(fnamed, data_type);
+  function_application_exprt rhs_length(symbol_exprt(fnamel), length_type);
+  function_application_exprt rhs_data(
+    symbol_exprt(fnamed), data_type.subtype());
+
+  exprt::operandst processed_arguments=process_arguments(
+    goto_program, target, arguments, location, signature);
+  rhs_length.arguments()=processed_arguments;
+  rhs_data.arguments()=processed_arguments;
+
+  symbol_exprt tmp_length=new_tmp_symbol("tmp_length", length_type);
+  symbol_exprt tmp_array=new_tmp_symbol("tmp_array", data_type.subtype());
+  member_exprt lhs_length(deref, "length", length_type);
+  member_exprt lhs_data(deref, "data", tmp_array.type());
+
+  // lhs=malloc(String *)
+  assert(object_size.is_not_nil()); // got nil object_size
+  side_effect_exprt malloc_expr(ID_malloc);
+  malloc_expr.copy_to_operands(object_size);
+  malloc_expr.type()=pointer_typet(object_type);
+  malloc_expr.add_source_location()=location;
+
+  // Adding a string expr in the map
+  refined_string_typet ref_type(length_type, data_type.subtype().subtype());
+  string_exprt str(tmp_length, tmp_array, ref_type);
+  symbol_exprt cprover_string_sym=new_tmp_symbol(
+    "tmp_cprover_string", ref_type);
+
+  std::list<code_assignt> assigns;
+  assigns.emplace_back(lhs, malloc_expr);
+  assigns.emplace_back(tmp_length, rhs_length);
+  assigns.emplace_back(lhs_length, tmp_length);
+  assigns.emplace_back(tmp_array, rhs_data);
+  assigns.emplace_back(cprover_string_sym, str);
+  assigns.emplace_back(lhs_data, address_of_exprt(tmp_array));
+  insert_assignments(goto_program, target, target->function, location, assigns);
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_string_function
+
+  Inputs: a position in a goto program, a function name, an expression lhs,
+          a function type, name, arguments, a location and a signature string
+
+ Purpose: at the current position replace `lhs=s.some_function(x,...)`
+          by `lhs=function_name(s,x,...)`;
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_string_function(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const exprt &lhs,
+  const code_typet &function_type,
+  const irep_idt &function_name,
+  const exprt::operandst &arguments,
+  const source_locationt &location,
+  const std::string &signature)
+{
+  if(signature.length()>0)
+  {
+    if(signature.back()=='S')
+    {
+      code_typet ft=function_type;
+      ft.return_type()=jls_ptr;
+      typecast_exprt lhs2(lhs, jls_ptr);
+
+      make_string_assign(
+        goto_program,
+        target,
+        lhs2,
+        ft,
+        function_name,
+        arguments,
+        location,
+         signature);
+    }
+    else
+      make_normal_assign(
+      goto_program,
+      target,
+      lhs,
+      function_type,
+      function_name,
+      arguments,
+      location,
+      signature);
+  }
+  else if(implements_java_char_sequence(function_type.return_type()))
+    make_string_assign(
+      goto_program,
+      target,
+      lhs,
+      function_type,
+      function_name,
+      arguments,
+      location,
+      signature);
+  else
+    make_normal_assign(
+      goto_program,
+      target,
+      lhs,
+      function_type,
+      function_name,
+      arguments,
+      location,
+      signature);
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_string_function
+
+  Inputs: a position in a goto program, a function name and two Boolean options
+
+ Purpose: at the current position replace `lhs=s.some_function(x,...)`
+          by `lhs=function_name(s,x,...)`;
+          option `assign_first_arg` uses `s` instead of `lhs` in the resulting
+          expression, Warning : it assumes that `s` is string-like
+          option `skip_first_arg`, removes `s` from the arguments, ie `x` is
+          the first one;
+          arguments that are string (TODO: and char array) are replaced
+          by string_exprt
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_string_function(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const irep_idt &function_name,
+  const std::string &signature,
+  bool assign_first_arg,
+  bool skip_first_arg)
+{
+  code_function_callt &function_call=to_code_function_call(target->code);
+  code_typet function_type=to_code_type(function_call.function().type());
+  code_typet new_type;
+  const source_locationt &loc=function_call.source_location();
+  declare_function(function_name, function_type);
+  function_application_exprt rhs;
+  std::vector<exprt> args;
+  if(assign_first_arg)
+    rhs.type()=function_call.arguments()[0].type();
+  else
+    rhs.type()=function_type.return_type();
+  rhs.add_source_location()=function_call.source_location();
+  rhs.function()=symbol_exprt(function_name);
+
+  std::size_t start_index=skip_first_arg?1:0;
+  for(std::size_t i=start_index; i<function_call.arguments().size(); i++)
+  {
+    args.push_back(function_call.arguments()[i]);
+    new_type.parameters().push_back(function_type.parameters()[i]);
+  }
+
+  std::string new_sig=signature;
+  exprt lhs;
+  if(assign_first_arg)
+  {
+    lhs=function_call.arguments()[0];
+    std::size_t size=function_call.arguments().size();
+    if(signature.length()<=size)
+      new_sig.resize(size+1, '_');
+
+    new_sig.replace(size, 1, "S");
+  }
+  else
+    lhs=function_call.lhs();
+
+  // TODO: not sure we have to do that
+  if(lhs.id()==ID_typecast)
+    lhs=to_typecast_expr(lhs).op();
+  // ----------------
+
+  new_type.return_type()=lhs.type();
+
+  make_string_function(
+    goto_program, target, lhs, new_type, function_name, args, loc, new_sig);
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_string_function_call
+
+  Inputs: a position in a goto program and a function name
+
+ Purpose: at the current position, replace `s.some_function(x,...)` by
+          `s=function_name(x,...)`
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_string_function_call(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const irep_idt &function_name,
+  const std::string &signature)
+{
+  make_string_function(
+    goto_program, target, function_name, signature, true, true);
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_string_function_side_effect
+
+  Inputs: a position in a goto program and a function name
+
+ Purpose: at the current position, replace `r=s.some_function(x,...)` by
+          > tmp=function_name(x,...)
+          > s->data=tmp.data
+          > s->length=tmp.length
+          > r=s
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_string_function_side_effect(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const irep_idt &function_name,
+  const std::string &signature)
+{
+  code_function_callt function_call=to_code_function_call(target->code);
+  source_locationt loc=function_call.source_location();
+  std::list<code_assignt> assignments;
+  exprt lhs=function_call.lhs();
+  exprt s=function_call.arguments()[0];
+  code_typet function_type=to_code_type(function_call.type());
+
+  function_type.return_type()=s.type();
+
+  if(lhs.is_not_nil())
+  {
+    symbol_exprt tmp_string=new_tmp_symbol(
+      "tmp_string_side_effect", lhs.type());
+
+    make_string_assign(
+      goto_program,
+      target,
+      tmp_string,
+      function_type,
+      function_name,
+      function_call.arguments(),
+      loc,
+      signature);
+    dereference_exprt deref_lhs(s, s.type().subtype());
+    typet data_type, length_type;
+    get_data_and_length_type_of_string(deref_lhs, data_type, length_type);
+    member_exprt lhs_data(deref_lhs, "data", data_type);
+    member_exprt lhs_length(deref_lhs, "length", length_type);
+    dereference_exprt deref_rhs(tmp_string, s.type().subtype());
+    member_exprt rhs_data(deref_rhs, "data", data_type);
+    member_exprt rhs_length(deref_rhs, "length", length_type);
+    assignments.emplace_back(lhs_length, rhs_length);
+    assignments.emplace_back(lhs_data, rhs_data);
+    assignments.emplace_back(lhs, s);
+    target=goto_program.insert_after(target);
+    insert_assignments(
+      goto_program, target, target->function, loc, assignments);
+  }
+  else
+  {
+    make_string_function(
+      goto_program, target, function_name, signature, true, false);
+  }
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::build_function_application
+
+  Inputs: a function name, a type, a location and a vector of arguments
+
+ Outputs: a function application expression
+
+ Purpose: declare a function and construct an function application expression
+          with the given function name, type, location and arguments
+
+\*******************************************************************/
+
+function_application_exprt
+  string_refine_preprocesst::build_function_application(
+    const irep_idt &function_name,
+    const typet &type,
+    const source_locationt &location,
+    const exprt::operandst &arguments)
+{
+  declare_function(function_name, type);
+  function_application_exprt function_app(symbol_exprt(function_name), type);
+  function_app.add_source_location()=location;
+  for(const auto &arg : arguments)
+    function_app.arguments().push_back(arg);
+
+  return function_app;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::make_to_char_array_function
+
+  Inputs: a goto program and a position in that goto program
+
+ Purpose: at the given position replace `return_tmp0=s.toCharArray()` with:
+          > return_tmp0 = malloc(array[char]);
+          > return_tmp0->data=&((s->data)[0])
+          > return_tmp0->length=s->length
+
+\*******************************************************************/
+
+void string_refine_preprocesst::make_to_char_array_function(
+  goto_programt &goto_program, goto_programt::targett &target)
+{
+  const code_function_callt &function_call=to_code_function_call(target->code);
+  source_locationt location=function_call.source_location();
+
+  assert(function_call.arguments().size()>=1);
+  const exprt &string_argument=function_call.arguments()[0];
+  assert(is_java_string_pointer_type(string_argument.type()));
+
+  typet deref_type=function_call.lhs().type().subtype();
+  const exprt &lhs=function_call.lhs();
+  dereference_exprt deref_lhs(lhs, deref_type);
+
+  dereference_exprt deref(string_argument, string_argument.type().subtype());
+  typet length_type, data_type;
+  get_data_and_length_type_of_string(deref, data_type, length_type);
+  std::list<code_assignt> assignments;
+
+  // lhs=malloc(array[char])
+  typet object_type=ns.follow(deref_type);
+  exprt object_size=size_of_expr(object_type, ns);
+
+  if(object_size.is_nil())
+    debug() << "string_refine_preprocesst::make_to_char_array_function "
+            << "got nil object_size" << eom;
+
+  side_effect_exprt malloc_expr(ID_malloc);
+  malloc_expr.copy_to_operands(object_size);
+  malloc_expr.type()=pointer_typet(object_type);
+  malloc_expr.add_source_location()=location;
+  assignments.emplace_back(lhs, malloc_expr);
+
+
+  // &((s->data)[0])
+  exprt rhs_data=get_data(deref, data_type);
+  dereference_exprt rhs_array(rhs_data, data_type.subtype());
+  exprt first_index=from_integer(0, java_int_type());
+  index_exprt first_element(rhs_array, first_index, java_char_type());
+  address_of_exprt rhs_pointer(first_element);
+
+  // return_tmp0->data=&((s->data)[0])
+  exprt lhs_data=get_data(deref_lhs, data_type);
+  assignments.emplace_back(lhs_data, rhs_pointer);
+
+  // return_tmp0->length=s->length
+  exprt rhs_length=get_length(deref, length_type);
+  exprt lhs_length=get_length(deref_lhs, length_type);
+  assignments.emplace_back(lhs_length, rhs_length);
+  insert_assignments(
+    goto_program, target, target->function, location, assignments);
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::process_arguments
+
+  Inputs: a goto program, a position, a list of expressions, a location and a
+          signature
+
+ Outputs: a list of expressions
+
+ Purpose: for each expression that is a string or that is at a position with
+          an 'S' character in the signature, we declare a new `cprover_string`
+          whose contents is deduced from the expression and replace the
+          expression by this cprover_string in the output list;
+          in the other case the expression is kept as is for the output list.
+
+\*******************************************************************/
+
+exprt::operandst string_refine_preprocesst::process_arguments(
+  goto_programt &goto_program,
+  goto_programt::targett &target,
+  const exprt::operandst &arguments,
+  const source_locationt &location,
+  const std::string &signature)
+{
+  exprt::operandst new_arguments;
+
+  for(std::size_t i=0; i<arguments.size(); i++)
+  {
+    exprt arg=arguments[i];
+    if(i<signature.length() && signature[i]=='S')
+    {
+      while(arg.id()==ID_typecast)
+        arg=arg.op0();
+      if(!implements_java_char_sequence(arg.type()))
+        arg=typecast_exprt(arg, jls_ptr);
+    }
+    arg=make_cprover_string_assign(goto_program, target, arg, location);
+    typet type=ns.follow(arg.type());
+    if(is_java_char_array_pointer_type(type))
+    {
+      arg=make_cprover_char_array_assign(goto_program, target, arg, location);
+    }
+    new_arguments.push_back(arg);
+  }
+  return new_arguments;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::function_signature
+
+  Inputs: the name of a cprover string function
+
+ Outputs: a signature string
+
+ Purpose: if the signature of the given function is defined, return it
+          otherwise return an empty string
+
+\*******************************************************************/
+
+std::string string_refine_preprocesst::function_signature(
+  const irep_idt &function_id)
+{
+  auto it=signatures.find(function_id);
+  if(it!=signatures.end())
+    return it->second;
+  else return "";
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::replace_string_calls
+
+  Inputs: a function in a goto_program
+
+ Purpose: goes through the instructions, replace function calls to string
+          function by equivalent instructions using functions defined
+          for the string solver, replace string literals by string
+          expressions of the type used by the string solver
+
+\*******************************************************************/
+
+void string_refine_preprocesst::replace_string_calls(
+  goto_functionst::function_mapt::iterator f_it)
+{
+  goto_programt &goto_program=f_it->second.body;
+
+  Forall_goto_program_instructions(target, goto_program)
+  {
+    if(target->is_function_call())
+    {
+      code_function_callt &function_call=to_code_function_call(target->code);
+
+      if(function_call.function().id()==ID_symbol)
+      {
+        const irep_idt &function_id=
+          to_symbol_expr(function_call.function()).get_identifier();
+        std::string signature=function_signature(function_id);
+        auto it=string_functions.find(function_id);
+        if(it!=string_functions.end())
+          make_string_function(
+            goto_program, target, it->second, signature, false, false);
+
+        it=side_effect_functions.find(function_id);
+        if(it!=side_effect_functions.end())
+          make_string_function_side_effect(
+            goto_program, target, it->second, signature);
+
+        it=string_function_calls.find(function_id);
+        if(it!=string_function_calls.end())
+          make_string_function_call(
+            goto_program, target, it->second, signature);
+
+        if(function_id==irep_idt("java::java.lang.String.toCharArray:()[C"))
+          make_to_char_array_function(goto_program, target);
+      }
+    }
+    else
+    {
+      if(target->is_assign())
+      {
+        // In assignments we replace string literals and C string functions
+        code_assignt assignment=to_code_assign(target->code);
+
+        exprt new_rhs=assignment.rhs();
+        code_assignt new_assignment(assignment.lhs(), new_rhs);
+
+        exprt uncasted=new_rhs;
+
+        if(uncasted.id()==ID_typecast)
+          uncasted=to_typecast_expr(uncasted).op0();
+
+        if(new_rhs.id()==ID_function_application)
+        {
+          function_application_exprt f=to_function_application_expr(new_rhs);
+          const exprt &name=f.function();
+          assert(name.id()==ID_symbol);
+          const irep_idt &id=to_symbol_expr(name).get_identifier();
+          auto it=c_string_functions.find(id);
+          if(it!=c_string_functions.end())
+          {
+            declare_function(it->second, f.type());
+            f.function()=symbol_exprt(it->second);
+            new_assignment=code_assignt(assignment.lhs(), f);
+          }
+        }
+
+        new_assignment.add_source_location()=assignment.source_location();
+        target->make_assignment();
+        target->code=new_assignment;
+      }
+    }
+  }
+  return;
+}
+
+/*******************************************************************\
+
+Function: string_refine_preprocesst::initialize_string_function_table
+
+ Purpose: fill maps with correspondance from java method names to cprover
+          functions
+
+\*******************************************************************/
+
+void string_refine_preprocesst::initialize_string_function_table()
+{
+  string_functions["java::java.lang.String.codePointAt:(I)I"]=
+    ID_cprover_string_code_point_at_func;
+  string_functions["java::java.lang.String.codePointBefore:(I)I"]=
+    ID_cprover_string_code_point_before_func;
+  string_functions["java::java.lang.String.codePointCount:(II)I"]=
+    ID_cprover_string_code_point_count_func;
+  string_functions["java::java.lang.String.offsetByCodePoints:(II)I"]=
+    ID_cprover_string_offset_by_code_point_func;
+  string_functions["java::java.lang.String.hashCode:()I"]=
+    ID_cprover_string_hash_code_func;
+  string_functions["java::java.lang.String.indexOf:(I)I"]=
+    ID_cprover_string_index_of_func;
+  string_functions["java::java.lang.String.indexOf:(II)I"]=
+    ID_cprover_string_index_of_func;
+  string_functions["java::java.lang.String.indexOf:(Ljava/lang/String;)I"]=
+    ID_cprover_string_index_of_func;
+  string_functions["java::java.lang.String.indexOf:(Ljava/lang/String;I)I"]=
+    ID_cprover_string_index_of_func;
+  string_functions["java::java.lang.String.lastIndexOf:(I)I"]=
+    ID_cprover_string_last_index_of_func;
+  string_functions["java::java.lang.String.lastIndexOf:(II)I"]=
+    ID_cprover_string_last_index_of_func;
+  string_functions
+    ["java::java.lang.String.lastIndexOf:(Ljava/lang/String;)I"]=
+    ID_cprover_string_last_index_of_func;
+  string_functions
+    ["java::java.lang.String.lastIndexOf:(Ljava/lang/String;I)I"]=
+    ID_cprover_string_last_index_of_func;
+  string_functions
+    ["java::java.lang.String.concat:(Ljava/lang/String;)Ljava/lang/String;"]=
+    ID_cprover_string_concat_func;
+  string_functions["java::java.lang.String.length:()I"]=
+    ID_cprover_string_length_func;
+  string_functions["java::java.lang.StringBuilder.length:()I"]=
+    ID_cprover_string_length_func;
+  string_functions["java::java.lang.String.equals:(Ljava/lang/Object;)Z"]=
+    ID_cprover_string_equal_func;
+  string_functions
+    ["java::java.lang.String.equalsIgnoreCase:(Ljava/lang/String;)Z"]=
+    ID_cprover_string_equals_ignore_case_func;
+  string_functions["java::java.lang.String.startsWith:(Ljava/lang/String;)Z"]=
+    ID_cprover_string_startswith_func;
+  string_functions
+    ["java::java.lang.String.startsWith:(Ljava/lang/String;I)Z"]=
+    ID_cprover_string_startswith_func;
+  string_functions["java::java.lang.String.endsWith:(Ljava/lang/String;)Z"]=
+    ID_cprover_string_endswith_func;
+  string_functions["java::java.lang.String.substring:(II)Ljava/lang/String;"]=
+    ID_cprover_string_substring_func;
+  string_functions["java::java.lang.String.substring:(II)Ljava/lang/String;"]=
+    ID_cprover_string_substring_func;
+  string_functions["java::java.lang.String.substring:(I)Ljava/lang/String;"]=
+    ID_cprover_string_substring_func;
+  string_functions
+    ["java::java.lang.StringBuilder.substring:(II)Ljava/lang/String;"]=
+    ID_cprover_string_substring_func;
+  string_functions
+    ["java::java.lang.StringBuilder.substring:(I)Ljava/lang/String;"]=
+    ID_cprover_string_substring_func;
+  string_functions
+    ["java::java.lang.String.subSequence:(II)Ljava/lang/CharSequence;"]=
+    ID_cprover_string_substring_func;
+  string_functions["java::java.lang.String.trim:()Ljava/lang/String;"]=
+    ID_cprover_string_trim_func;
+  string_functions["java::java.lang.String.toLowerCase:()Ljava/lang/String;"]=
+    ID_cprover_string_to_lower_case_func;
+  string_functions["java::java.lang.String.toUpperCase:()Ljava/lang/String;"]=
+    ID_cprover_string_to_upper_case_func;
+  string_functions["java::java.lang.String.replace:(CC)Ljava/lang/String;"]=
+    ID_cprover_string_replace_func;
+  string_functions
+    ["java::java.lang.String.contains:(Ljava/lang/CharSequence;)Z"]=
+    ID_cprover_string_contains_func;
+  string_functions["java::java.lang.String.compareTo:(Ljava/lang/String;)I"]=
+    ID_cprover_string_compare_to_func;
+  string_functions["java::java.lang.String.intern:()Ljava/lang/String;"]=
+    ID_cprover_string_intern_func;
+  string_functions["java::java.lang.String.isEmpty:()Z"]=
+    ID_cprover_string_is_empty_func;
+  string_functions["java::java.lang.String.charAt:(I)C"]=
+    ID_cprover_string_char_at_func;
+  string_functions["java::java.lang.StringBuilder.charAt:(I)C"]=
+    ID_cprover_string_char_at_func;
+  string_functions["java::java.lang.CharSequence.charAt:(I)C"]=
+    ID_cprover_string_char_at_func;
+  string_functions
+    ["java::java.lang.StringBuilder.toString:()Ljava/lang/String;"]=
+    ID_cprover_string_copy_func;
+
+  string_functions["java::java.lang.String.valueOf:(F)Ljava/lang/String;"]=
+    ID_cprover_string_of_float_func;
+  string_functions["java::java.lang.Float.toString:(F)Ljava/lang/String;"]=
+    ID_cprover_string_of_float_func;
+  string_functions["java::java.lang.Integer.toString:(I)Ljava/lang/String;"]=
+    ID_cprover_string_of_int_func;
+  string_functions["java::java.lang.String.valueOf:(I)Ljava/lang/String;"]=
+    ID_cprover_string_of_int_func;
+  string_functions["java::java.lang.Integer.toHexString:(I)Ljava/lang/String;"]=
+    ID_cprover_string_of_int_hex_func;
+  string_functions["java::java.lang.String.valueOf:(L)Ljava/lang/String;"]=
+    ID_cprover_string_of_long_func;
+  string_functions["java::java.lang.String.valueOf:(D)Ljava/lang/String;"]=
+    ID_cprover_string_of_double_func;
+  string_functions["java::java.lang.String.valueOf:(Z)Ljava/lang/String;"]=
+    ID_cprover_string_of_bool_func;
+  string_functions["java::java.lang.String.valueOf:(C)Ljava/lang/String;"]=
+    ID_cprover_string_of_char_func;
+  string_functions["java::java.lang.Integer.parseInt:(Ljava/lang/String;)I"]=
+    ID_cprover_string_parse_int_func;
+
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(Ljava/lang/String;)"
+      "Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_func;
+  side_effect_functions["java::java.lang.StringBuilder.setCharAt:(IC)V"]=
+    ID_cprover_string_char_set_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(I)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_int_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(J)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_long_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(Z)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_bool_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(C)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_char_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(D)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_double_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:(F)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_float_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.appendCodePoint:(I)"
+     "Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_code_point_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.delete:(II)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_delete_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.deleteCharAt:(I)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_delete_char_at_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(ILjava/lang/String;)"
+     "Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(II)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_int_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(IJ)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_long_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(IC)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_char_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(IZ)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_bool_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.setLength:(I)V"]=
+    ID_cprover_string_set_length_func;
+
+
+
+  side_effect_functions
+    ["java::java.lang.StringBuilder.append:([C)"
+      "Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_concat_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(I[CII)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_func;
+  side_effect_functions
+    ["java::java.lang.StringBuilder.insert:(I[C)Ljava/lang/StringBuilder;"]=
+    ID_cprover_string_insert_func;
+    // TODO clean irep ids from insert_char_array etc...
+
+  string_function_calls
+    ["java::java.lang.String.<init>:(Ljava/lang/String;)V"]=
+    ID_cprover_string_copy_func;
+  string_function_calls
+    ["java::java.lang.String.<init>:(Ljava/lang/StringBuilder;)V"]=
+    ID_cprover_string_copy_func;
+  string_function_calls
+    ["java::java.lang.StringBuilder.<init>:(Ljava/lang/String;)V"]=
+    ID_cprover_string_copy_func;
+  string_function_calls["java::java.lang.String.<init>:()V"]=
+    ID_cprover_string_empty_string_func;
+  string_function_calls["java::java.lang.StringBuilder.<init>:()V"]=
+    ID_cprover_string_empty_string_func;
+
+  string_function_calls["java::java.lang.String.<init>:([C)V"]=
+    ID_cprover_string_copy_func;
+  string_function_calls["java::java.lang.String.<init>:([CII)V"]=
+    ID_cprover_string_copy_func;
+
+  string_functions
+    ["java::java.lang.String.valueOf:([CII)Ljava/lang/String;"]=
+    ID_cprover_string_copy_func;
+  string_functions
+    ["java::java.lang.String.valueOf:([C)Ljava/lang/String;"]=
+    ID_cprover_string_copy_func;
+  string_functions
+    ["java::java.lang.String.copyValueOf:([CII)Ljava/lang/String;"]=
+    ID_cprover_string_copy_func;
+  string_functions
+    ["java::java.lang.String.copyValueOf:([C)Ljava/lang/String;"]=
+    ID_cprover_string_copy_func;
+
+  c_string_functions["__CPROVER_uninterpreted_string_literal_func"]=
+    ID_cprover_string_literal_func;
+  c_string_functions["__CPROVER_uninterpreted_string_char_at_func"]=
+    ID_cprover_string_char_at_func;
+  c_string_functions["__CPROVER_uninterpreted_string_equal_func"]=
+    ID_cprover_string_equal_func;
+  c_string_functions["__CPROVER_uninterpreted_string_concat_func"]=
+    ID_cprover_string_concat_func;
+  c_string_functions["__CPROVER_uninterpreted_string_length_func"]=
+    ID_cprover_string_length_func;
+  c_string_functions["__CPROVER_uninterpreted_string_substring_func"]=
+    ID_cprover_string_substring_func;
+  c_string_functions["__CPROVER_uninterpreted_string_is_prefix_func"]=
+    ID_cprover_string_is_prefix_func;
+  c_string_functions["__CPROVER_uninterpreted_string_is_suffix_func"]=
+    ID_cprover_string_is_suffix_func;
+  c_string_functions["__CPROVER_uninterpreted_string_contains_func"]=
+    ID_cprover_string_contains_func;
+  c_string_functions["__CPROVER_uninterpreted_string_index_of_func"]=
+    ID_cprover_string_index_of_func;
+  c_string_functions["__CPROVER_uninterpreted_string_last_index_of_func"]=
+    ID_cprover_string_last_index_of_func;
+  c_string_functions["__CPROVER_uninterpreted_string_char_set_func"]=
+    ID_cprover_string_char_set_func;
+  c_string_functions["__CPROVER_uninterpreted_string_copy_func"]=
+    ID_cprover_string_copy_func;
+  c_string_functions["__CPROVER_uninterpreted_string_parse_int_func"]=
+    ID_cprover_string_parse_int_func;
+  c_string_functions["__CPROVER_uninterpreted_string_of_int_func"]=
+    ID_cprover_string_of_int_func;
+
+  signatures["java::java.lang.String.equals:(Ljava/lang/Object;)Z"]="SSZ";
+  signatures["java::java.lang.String.contains:(Ljava/lang/CharSequence;)Z"]=
+    "SSZ";
+  signatures["java::java.lang.StringBuilder.insert:(IZ)"
+             "Ljava/lang/StringBuilder;"]="SIZS";
+  signatures["java::java.lang.StringBuilder.insert:(IJ)"
+             "Ljava/lang/StringBuilder;"]="SIJS";
+  signatures["java::java.lang.StringBuilder.insert:(II)"
+             "Ljava/lang/StringBuilder;"]="SIIS";
+  signatures["java::java.lang.StringBuilder.insert:(IC)"
+             "Ljava/lang/StringBuilder;"]="SICS";
+  signatures["java::java.lang.StringBuilder.insert:(ILjava/lang/String;)"
+             "Ljava/lang/StringBuilder;"]="SISS";
+  signatures["java::java.lang.StringBuilder.insert:(ILjava/lang/String;)"
+             "Ljava/lang/StringBuilder;"]="SISS";
+  signatures["java::java.lang.StringBuilder.insert:(I[C)"
+             "Ljava/lang/StringBuilder;"]="SI[S";
+  signatures["java::java.lang.String.intern:()Ljava/lang/String;"]="SV";
+}
+
+/*******************************************************************\
+
+Constructor: string_refine_preprocesst::string_refine_preprocesst
+
+     Inputs: a symbol table, goto functions, a message handler
+
+    Purpose: process the goto function by replacing calls to string functions
+
+\*******************************************************************/
+
+string_refine_preprocesst::string_refine_preprocesst(
+  symbol_tablet &_symbol_table,
+  goto_functionst &_goto_functions,
+  message_handlert &_message_handler):
+    messaget(_message_handler),
+    ns(_symbol_table),
+    symbol_table(_symbol_table),
+    goto_functions(_goto_functions),
+    next_symbol_id(0),
+    jls_ptr(symbol_typet("java::java.lang.String"))
+{
+  initialize_string_function_table();
+  Forall_goto_functions(it, goto_functions)
+    replace_string_calls(it);
+}
diff --git a/src/goto-programs/string_refine_preprocess.h b/src/goto-programs/string_refine_preprocess.h
new file mode 100644
index 00000000000..065a86e968f
--- /dev/null
+++ b/src/goto-programs/string_refine_preprocess.h
@@ -0,0 +1,198 @@
+/*******************************************************************\
+
+Module: Preprocess a goto-programs so that calls to the java String
+        library are recognized by the PASS algorithm
+
+Author: Romain Brenguier
+
+Date:   September 2016
+
+\*******************************************************************/
+
+#ifndef CPROVER_GOTO_PROGRAMS_STRING_REFINE_PREPROCESS_H
+#define CPROVER_GOTO_PROGRAMS_STRING_REFINE_PREPROCESS_H
+
+#include <goto-programs/goto_model.h>
+#include <util/ui_message.h>
+#include <util/string_expr.h>
+
+class string_refine_preprocesst:public messaget
+{
+ public:
+  string_refine_preprocesst(
+    symbol_tablet &, goto_functionst &, message_handlert &);
+
+ private:
+  namespacet ns;
+  symbol_tablet & symbol_table;
+  goto_functionst & goto_functions;
+
+  typedef std::unordered_map<irep_idt, irep_idt, irep_id_hash> id_mapt;
+  typedef std::unordered_map<exprt, exprt, irep_hash> expr_mapt;
+
+  // Map name of Java string functions to there equivalent in the solver
+  id_mapt side_effect_functions;
+  id_mapt string_functions;
+  id_mapt c_string_functions;
+  id_mapt string_function_calls;
+
+  std::unordered_map<irep_idt, std::string, irep_id_hash> signatures;
+
+  // unique id for each newly created symbols
+  int next_symbol_id;
+
+  void initialize_string_function_table();
+
+  static bool check_java_type(const typet &type, const std::string &tag);
+
+  static bool is_java_string_pointer_type(const typet &type);
+
+  static bool is_java_string_type(const typet &type);
+
+  static bool is_java_string_builder_type(const typet &type);
+
+  static bool is_java_string_builder_pointer_type(const typet &type);
+
+  static bool is_java_char_sequence_type(const typet &type);
+
+  static bool is_java_char_sequence_pointer_type(const typet &type);
+
+  static bool is_java_char_array_type(const typet &type);
+
+  static bool is_java_char_array_pointer_type(const typet &type);
+
+  static bool implements_java_char_sequence(const typet &type)
+  {
+      return
+        is_java_char_sequence_pointer_type(type) ||
+        is_java_string_builder_pointer_type(type) ||
+        is_java_string_pointer_type(type);
+  }
+
+  symbol_exprt new_tmp_symbol(const std::string &name, const typet &type);
+
+  symbol_exprt new_symbol(
+    const std::string &prefix, const typet &type, bool static_lifetime=true);
+
+  // get the data member of a java string
+  static exprt get_data(const exprt &string, const typet &data_type)
+  {
+    return member_exprt(string, "data", data_type);
+  }
+
+  // get the length member of a java string
+  exprt get_length(const exprt &string, const typet &length_type)
+  {
+    return member_exprt(string, "length", length_type);
+  }
+
+  // type of pointers to string
+  pointer_typet jls_ptr;
+  exprt replace_string(const exprt &in);
+  exprt replace_string_in_assign(const exprt &in);
+
+  void insert_assignments(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    irep_idt function,
+    source_locationt location,
+    const std::list<code_assignt> &va);
+
+  exprt replace_string_pointer(const exprt &in);
+
+  // Replace string builders by expression of the mapping and make
+  // assignments for strings as string_exprt
+  exprt::operandst process_arguments(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const exprt::operandst &arguments,
+    const source_locationt &location,
+    const std::string &signature="");
+
+  // Signature of the named function if it is defined in the signature map,
+  // empty string otherwise
+  std::string function_signature(const irep_idt &function_id);
+
+  void declare_function(irep_idt function_name, const typet &type);
+
+  void get_data_and_length_type_of_string(
+    const exprt &expr, typet &data_type, typet &length_type);
+
+  void get_data_and_length_type_of_char_array(
+    const exprt &expr, typet &data_type, typet &length_type);
+
+  function_application_exprt build_function_application(
+    const irep_idt &function_name,
+    const typet &type,
+    const source_locationt &location,
+    const exprt::operandst &arguments);
+
+  void make_normal_assign(
+    goto_programt &goto_program,
+    goto_programt::targett target,
+    const exprt &lhs,
+    const code_typet &function_type,
+    const irep_idt &function_name,
+    const exprt::operandst &arguments,
+    const source_locationt &location,
+    const std::string &signature="");
+
+  void make_string_assign(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const exprt &lhs,
+    const code_typet &function_type,
+    const irep_idt &function_name,
+    const exprt::operandst &arguments,
+    const source_locationt &location,
+    const std::string &signature);
+
+  exprt make_cprover_string_assign(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const exprt &rhs,
+    const source_locationt &location);
+
+  string_exprt make_cprover_char_array_assign(
+    goto_programt &goto_program,
+    goto_programt::targett &i_it,
+    const exprt &rhs,
+    const source_locationt &location);
+
+  void make_string_function(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const irep_idt &function_name,
+    const std::string &signature,
+    bool assign_first_arg=false,
+    bool skip_first_arg=false);
+
+  void make_string_function(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const exprt &lhs,
+    const code_typet &function_type,
+    const irep_idt &function_name,
+    const exprt::operandst &arguments,
+    const source_locationt &location,
+    const std::string &signature);
+
+  void make_string_function_call(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const irep_idt &function_name,
+    const std::string &signature);
+
+  void make_string_function_side_effect(
+    goto_programt &goto_program,
+    goto_programt::targett &target,
+    const irep_idt &function_name,
+    const std::string &signature);
+
+  void make_to_char_array_function(
+    goto_programt &goto_program, goto_programt::targett &);
+
+  void replace_string_calls(goto_functionst::function_mapt::iterator f_it);
+};
+
+#endif
diff --git a/src/java_bytecode/java_bytecode_convert_class.cpp b/src/java_bytecode/java_bytecode_convert_class.cpp
index f21b0bb1ce2..7f52c6ef77b 100644
--- a/src/java_bytecode/java_bytecode_convert_class.cpp
+++ b/src/java_bytecode/java_bytecode_convert_class.cpp
@@ -50,7 +50,16 @@ class java_bytecode_convert_classt:public messaget
       convert(parse_tree.parsed_class);
     else if(string_refinement_enabled &&
             parse_tree.parsed_class.name=="java.lang.String")
-      add_string_type();
+      add_string_type("java.lang.String");
+    else if(string_refinement_enabled &&
+            parse_tree.parsed_class.name=="java.lang.StringBuilder")
+      add_string_type("java.lang.StringBuilder");
+    else if(string_refinement_enabled &&
+            parse_tree.parsed_class.name=="java.lang.CharSequence")
+      add_string_type("java.lang.CharSequence");
+    else if(string_refinement_enabled &&
+            parse_tree.parsed_class.name=="java.lang.StringBuffer")
+      add_string_type("java.lang.StringBuffer");
     else
       generate_class_stub(parse_tree.parsed_class.name);
   }
@@ -72,7 +81,7 @@ class java_bytecode_convert_classt:public messaget
 
   void generate_class_stub(const irep_idt &class_name);
   void add_array_types();
-  void add_string_type();
+  void add_string_type(const irep_idt &class_name);
 };
 
 /*******************************************************************\
@@ -406,15 +415,17 @@ bool java_bytecode_convert_class(
 
 Function: java_bytecode_convert_classt::add_string_type
 
+  Inputs: a name for the class such as "java.lang.String"
+
  Purpose: Implements the java.lang.String type in the case that
           we provide an internal implementation.
 
 \*******************************************************************/
 
-void java_bytecode_convert_classt::add_string_type()
+void java_bytecode_convert_classt::add_string_type(const irep_idt &class_name)
 {
   class_typet string_type;
-  string_type.set_tag("java.lang.String");
+  string_type.set_tag(class_name);
   string_type.components().resize(3);
   string_type.components()[0].set_name("@java.lang.Object");
   string_type.components()[0].set_pretty_name("@java.lang.Object");
@@ -432,8 +443,8 @@ void java_bytecode_convert_classt::add_string_type()
   string_type.add_base(symbol_typet("java::java.lang.Object"));
 
   symbolt string_symbol;
-  string_symbol.name="java::java.lang.String";
-  string_symbol.base_name="java.lang.String";
+  string_symbol.name="java::"+id2string(class_name);
+  string_symbol.base_name=id2string(class_name);
   string_symbol.type=string_type;
   string_symbol.is_type=true;
 
@@ -445,8 +456,8 @@ void java_bytecode_convert_classt::add_string_type()
   symbolt string_equals_symbol;
   string_equals_symbol.name=
     "java::java.lang.String.equals:(Ljava/lang/Object;)Z";
-  string_equals_symbol.base_name="java.lang.String.equals";
-  string_equals_symbol.pretty_name="java.lang.String.equals";
+  string_equals_symbol.base_name=id2string(class_name)+".equals";
+  string_equals_symbol.pretty_name=id2string(class_name)+".equals";
   string_equals_symbol.mode=ID_java;
 
   code_typet string_equals_type;
diff --git a/src/solvers/Makefile b/src/solvers/Makefile
index 95ea7650274..136db5765c1 100644
--- a/src/solvers/Makefile
+++ b/src/solvers/Makefile
@@ -118,6 +118,17 @@ SRC = $(CHAFF_SRC) $(BOOLEFORCE_SRC) $(MINISAT_SRC) $(MINISAT2_SRC) \
       floatbv/float_utils.cpp floatbv/float_bv.cpp \
       refinement/bv_refinement_loop.cpp refinement/refine_arithmetic.cpp \
       refinement/refine_arrays.cpp \
+      refinement/string_refinement.cpp \
+      refinement/string_constraint_generator_code_points.cpp \
+      refinement/string_constraint_generator_comparison.cpp \
+      refinement/string_constraint_generator_concat.cpp \
+      refinement/string_constraint_generator_constants.cpp \
+      refinement/string_constraint_generator_indexof.cpp \
+      refinement/string_constraint_generator_insert.cpp \
+      refinement/string_constraint_generator_main.cpp \
+      refinement/string_constraint_generator_testing.cpp \
+      refinement/string_constraint_generator_transformation.cpp \
+      refinement/string_constraint_generator_valueof.cpp \
       miniBDD/miniBDD.cpp
 
 INCLUDES += -I .. \
diff --git a/src/solvers/refinement/refined_string_type.cpp b/src/solvers/refinement/refined_string_type.cpp
deleted file mode 100644
index 012d30eb8de..00000000000
--- a/src/solvers/refinement/refined_string_type.cpp
+++ /dev/null
@@ -1,145 +0,0 @@
-/********************************************************************\
-
-Module: Type for string expressions used by the string solver.
-        These string expressions contain a field `length`, of type
-        `index_type`, a field `content` of type `content_type`.
-        This module also defines functions to recognise the C and java
-        string types.
-
-Author: Romain Brenguier, romain.brenguier@diffblue.com
-
-\*******************************************************************/
-
-#include <util/cprover_prefix.h>
-
-#include "refined_string_type.h"
-
-/*******************************************************************\
-
-Constructor: refined_string_typet::refined_string_typet
-
-     Inputs: type of characters
-
-\*******************************************************************/
-
-refined_string_typet::refined_string_typet(
-  const typet &index_type, const typet &char_type)
-{
-  infinity_exprt infinite_index(index_type);
-  array_typet char_array(char_type, infinite_index);
-  components().emplace_back("length", index_type);
-  components().emplace_back("content", char_array);
-}
-
-/*******************************************************************\
-
-Function: refined_string_typet::is_c_string_type
-
-  Inputs: a type
-
- Outputs: Boolean telling whether the type is that of C strings
-
-\*******************************************************************/
-
-bool refined_string_typet::is_c_string_type(const typet &type)
-{
-  return
-    type.id()==ID_struct &&
-    to_struct_type(type).get_tag()==CPROVER_PREFIX"string";
-}
-
-/*******************************************************************\
-
-Function: refined_string_typet::is_java_string_pointer_type
-
-  Inputs: a type
-
- Outputs: Boolean telling whether the type is that of java string pointers
-
-\*******************************************************************/
-
-bool refined_string_typet::is_java_string_pointer_type(const typet &type)
-{
-  if(type.id()==ID_pointer)
-  {
-    const pointer_typet &pt=to_pointer_type(type);
-    const typet &subtype=pt.subtype();
-    return is_java_string_type(subtype);
-  }
-  return false;
-}
-
-/*******************************************************************\
-
-Function: refined_string_typet::is_java_string_type
-
-  Inputs: a type
-
- Outputs: Boolean telling whether the type is that of java string
-
-\*******************************************************************/
-
-bool refined_string_typet::is_java_string_type(const typet &type)
-{
-  if(type.id()==ID_symbol)
-  {
-    irep_idt tag=to_symbol_type(type).get_identifier();
-    return tag=="java::java.lang.String";
-  }
-  else if(type.id()==ID_struct)
-  {
-    irep_idt tag=to_struct_type(type).get_tag();
-    return tag=="java.lang.String";
-  }
-  return false;
-}
-
-/*******************************************************************\
-
-Function: refined_string_typet::is_java_string_builder_type
-
-  Inputs: a type
-
- Outputs: Boolean telling whether the type is that of java string builder
-
-\*******************************************************************/
-
-bool refined_string_typet::is_java_string_builder_type(const typet &type)
-{
-  if(type.id()==ID_pointer)
-  {
-    const pointer_typet &pt=to_pointer_type(type);
-    const typet &subtype=pt.subtype();
-    if(subtype.id()==ID_struct)
-    {
-      irep_idt tag=to_struct_type(subtype).get_tag();
-      return tag=="java.lang.StringBuilder";
-    }
-  }
-  return false;
-}
-
-/*******************************************************************\
-
-Function: refined_string_typet::is_java_char_sequence_type
-
-  Inputs: a type
-
- Outputs: Boolean telling whether the type is that of java char sequence
-
-\*******************************************************************/
-
-bool refined_string_typet::is_java_char_sequence_type(const typet &type)
-{
-  if(type.id()==ID_pointer)
-  {
-    const pointer_typet &pt=to_pointer_type(type);
-    const typet &subtype=pt.subtype();
-    if(subtype.id()==ID_struct)
-    {
-      const irep_idt &tag=to_struct_type(subtype).get_tag();
-      return tag=="java.lang.CharSequence";
-    }
-  }
-  return false;
-}
diff --git a/src/solvers/refinement/string_constraint.h b/src/solvers/refinement/string_constraint.h
index 61a6f3ebdd6..1bb460349b7 100644
--- a/src/solvers/refinement/string_constraint.h
+++ b/src/solvers/refinement/string_constraint.h
@@ -15,7 +15,7 @@ Author: Romain Brenguier, romain.brenguier@diffblue.com
 
 #include <langapi/language_ui.h>
 #include <solvers/refinement/bv_refinement.h>
-#include <solvers/refinement/refined_string_type.h>
+#include <util/refined_string_type.h>
 
 class string_constraintt: public exprt
 {
@@ -48,7 +48,6 @@ class string_constraintt: public exprt
     return operands()[4];
   }
 
-
  private:
   string_constraintt();
 
diff --git a/src/solvers/refinement/string_constraint_generator.h b/src/solvers/refinement/string_constraint_generator.h
index 2a56f09fddd..d8f3f17326e 100644
--- a/src/solvers/refinement/string_constraint_generator.h
+++ b/src/solvers/refinement/string_constraint_generator.h
@@ -14,7 +14,8 @@ Author: Romain Brenguier, romain.brenguier@diffblue.com
 #define CPROVER_SOLVERS_REFINEMENT_STRING_CONSTRAINT_GENERATOR_H
 
 #include <util/string_expr.h>
-#include <solvers/refinement/refined_string_type.h>
+#include <util/replace_expr.h>
+#include <util/refined_string_type.h>
 #include <solvers/refinement/string_constraint.h>
 
 class string_constraint_generatort
@@ -25,9 +26,17 @@ class string_constraint_generatort
   // to the axiom list.
 
   string_constraint_generatort():
-    mode(ID_unknown)
+    mode(ID_unknown),
+    max_string_length(-1),
+    force_printable_characters(false)
   { }
 
+  // Constraints on the maximal length of strings
+  int max_string_length;
+
+  // Should we add constraints on the characters
+  bool force_printable_characters;
+
   void set_mode(irep_idt _mode)
   {
     // only C and java modes supported
@@ -65,21 +74,22 @@ class string_constraint_generatort
   symbol_exprt fresh_univ_index(const irep_idt &prefix, const typet &type);
   symbol_exprt fresh_boolean(const irep_idt &prefix);
   string_exprt fresh_string(const refined_string_typet &type);
+  string_exprt get_string_expr(const exprt &expr);
+  string_exprt convert_java_string_to_string_exprt(
+    const exprt &underlying);
+  plus_exprt plus_exprt_with_overflow_check(const exprt &op1, const exprt &op2);
 
-  // We maintain a map from symbols to strings.
-  std::map<irep_idt, string_exprt> symbol_to_string;
+  // Maps unresolved symbols to the string_exprt that was created for them
+  std::map<irep_idt, string_exprt> unresolved_symbols;
 
-  string_exprt find_or_add_string_of_symbol(const symbol_exprt &sym);
+  // Set of strings that have been created by the generator
+  std::set<string_exprt> created_strings;
 
-  void assign_to_symbol(
-    const symbol_exprt &sym, const string_exprt &expr)
-  {
-    symbol_to_string[sym.get_identifier()]=expr;
-  }
+  string_exprt find_or_add_string_of_symbol(
+    const symbol_exprt &sym,
+    const refined_string_typet &ref_type);
 
-  string_exprt add_axioms_for_string_expr(const exprt &expr);
-  void set_string_symbol_equal_to_expr(
-    const symbol_exprt &sym, const exprt &str);
+  string_exprt add_axioms_for_refined_string(const exprt &expr);
 
   exprt add_axioms_for_function_application(
     const function_application_exprt &expr);
@@ -96,8 +106,11 @@ class string_constraint_generatort
   const std::size_t MAX_FLOAT_LENGTH=15;
   const std::size_t MAX_DOUBLE_LENGTH=30;
 
+  std::map<function_application_exprt, exprt> function_application_cache;
+
   static irep_idt extract_java_string(const symbol_exprt &s);
 
+  void add_default_axioms(const string_exprt &s);
   exprt axiom_for_is_positive_index(const exprt &x);
 
   // The following functions add axioms for the returned value
@@ -117,6 +130,9 @@ class string_constraint_generatort
   // The specification is partial: the actual value is not actually computed
   // but we ensure that hash codes of equal strings are equal.
   exprt add_axioms_for_hash_code(const function_application_exprt &f);
+  // To each string on which hash_code was called we associate a symbol
+  // representing the return value of the hash_code function.
+  std::map<string_exprt, exprt> hash_code_of_string;
 
   exprt add_axioms_for_is_empty(const function_application_exprt &f);
   exprt add_axioms_for_is_prefix(
@@ -224,7 +240,9 @@ class string_constraint_generatort
   // the start for negative number
   string_exprt add_axioms_from_float(const function_application_exprt &f);
   string_exprt add_axioms_from_float(
-    const exprt &f, bool double_precision=false);
+    const exprt &f,
+    const refined_string_typet &ref_type,
+    bool double_precision);
 
   // Add axioms corresponding to the String.valueOf(D) java function
   // TODO: the specifications is only partial
@@ -253,6 +271,7 @@ class string_constraint_generatort
   string_exprt add_axioms_for_code_point(
     const exprt &code_point, const refined_string_typet &ref_type);
   string_exprt add_axioms_for_java_char_array(const exprt &char_array);
+  exprt add_axioms_for_char_pointer(const function_application_exprt &fun);
   string_exprt add_axioms_for_if(const if_exprt &expr);
   exprt add_axioms_for_char_literal(const function_application_exprt &f);
 
@@ -270,6 +289,8 @@ class string_constraint_generatort
     const function_application_exprt &f);
 
   exprt add_axioms_for_parse_int(const function_application_exprt &f);
+  exprt add_axioms_for_correct_number_format(
+    const string_exprt &str, std::size_t max_size=10);
   exprt add_axioms_for_to_char_array(const function_application_exprt &f);
   exprt add_axioms_for_compare_to(const function_application_exprt &f);
 
@@ -278,6 +299,9 @@ class string_constraint_generatort
   // string pointers
   symbol_exprt add_axioms_for_intern(const function_application_exprt &f);
 
+  // Pool used for the intern method
+  std::map<string_exprt, symbol_exprt> intern_of_string;
+
   // Tells which language is used. C and Java are supported
   irep_idt mode;
 
@@ -293,14 +317,8 @@ class string_constraint_generatort
   exprt int_of_hex_char(const exprt &chr) const;
   exprt is_high_surrogate(const exprt &chr) const;
   exprt is_low_surrogate(const exprt &chr) const;
-  static exprt character_equals_ignore_case(
+  exprt character_equals_ignore_case(
     exprt char1, exprt char2, exprt char_a, exprt char_A, exprt char_Z);
-
-  // Pool used for the intern method
-  std::map<string_exprt, symbol_exprt> pool;
-
-  // Used to determine whether hashcode should be equal
-  std::map<string_exprt, symbol_exprt> hash;
 };
 
 #endif
diff --git a/src/solvers/refinement/string_constraint_generator_code_points.cpp b/src/solvers/refinement/string_constraint_generator_code_points.cpp
index 7c035a0d3e4..16763dfc97c 100644
--- a/src/solvers/refinement/string_constraint_generator_code_points.cpp
+++ b/src/solvers/refinement/string_constraint_generator_code_points.cpp
@@ -160,17 +160,18 @@ exprt string_constraint_generatort::add_axioms_for_code_point_at(
 {
   typet return_type=f.type();
   assert(return_type.id()==ID_signedbv);
-  string_exprt str=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt str=get_string_expr(args(f, 2)[0]);
   const exprt &pos=args(f, 2)[1];
 
   symbol_exprt result=fresh_symbol("char", return_type);
   exprt index1=from_integer(1, str.length().type());
   const exprt &char1=str[pos];
-  const exprt &char2=str[plus_exprt(pos, index1)];
+  const exprt &char2=str[plus_exprt_with_overflow_check(pos, index1)];
   exprt char1_as_int=typecast_exprt(char1, return_type);
   exprt char2_as_int=typecast_exprt(char2, return_type);
   exprt pair=pair_value(char1_as_int, char2_as_int, return_type);
-  exprt is_low=is_low_surrogate(str[plus_exprt(pos, index1)]);
+  exprt is_low=is_low_surrogate(
+    str[plus_exprt_with_overflow_check(pos, index1)]);
   exprt return_pair=and_exprt(is_high_surrogate(str[pos]), is_low);
 
   axioms.push_back(implies_exprt(return_pair, equal_exprt(result, pair)));
@@ -199,7 +200,7 @@ exprt string_constraint_generatort::add_axioms_for_code_point_before(
   typet return_type=f.type();
   assert(return_type.id()==ID_signedbv);
   symbol_exprt result=fresh_symbol("char", return_type);
-  string_exprt str=add_axioms_for_string_expr(args[0]);
+  string_exprt str=get_string_expr(args[0]);
 
   const exprt &char1=
     str[minus_exprt(args[1], from_integer(2, str.length().type()))];
@@ -234,7 +235,7 @@ Function: string_constraint_generatort::add_axioms_for_code_point_count
 exprt string_constraint_generatort::add_axioms_for_code_point_count(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt str=get_string_expr(args(f, 3)[0]);
   const exprt &begin=args(f, 3)[1];
   const exprt &end=args(f, 3)[2];
   const typet &return_type=f.type();
@@ -265,14 +266,15 @@ Function: string_constraint_generatort::add_axioms_for_offset_by_code_point
 exprt string_constraint_generatort::add_axioms_for_offset_by_code_point(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt str=get_string_expr(args(f, 3)[0]);
   const exprt &index=args(f, 3)[1];
   const exprt &offset=args(f, 3)[2];
   const typet &return_type=f.type();
   symbol_exprt result=fresh_symbol("offset_by_code_point", return_type);
 
-  exprt minimum=plus_exprt(index, offset);
-  exprt maximum=plus_exprt(index, plus_exprt(offset, offset));
+  exprt minimum=plus_exprt_with_overflow_check(index, offset);
+  exprt maximum=plus_exprt_with_overflow_check(
+    index, plus_exprt_with_overflow_check(offset, offset));
   axioms.push_back(binary_relation_exprt(result, ID_le, maximum));
   axioms.push_back(binary_relation_exprt(result, ID_ge, minimum));
 
diff --git a/src/solvers/refinement/string_constraint_generator_comparison.cpp b/src/solvers/refinement/string_constraint_generator_comparison.cpp
index 321282ee9c1..a51e2abe3cd 100644
--- a/src/solvers/refinement/string_constraint_generator_comparison.cpp
+++ b/src/solvers/refinement/string_constraint_generator_comparison.cpp
@@ -18,7 +18,9 @@ Function: string_constraint_generatort::add_axioms_for_equals
  Outputs: a expression of Boolean type
 
  Purpose: add axioms stating that the result is true exactly when the strings
-          represented by the arguments are equal
+          represented by the arguments are equal.
+          the variable ending in `witness_unequal` is -1 if the length differs
+          or an index at which the strings are different
 
 \*******************************************************************/
 
@@ -29,8 +31,8 @@ exprt string_constraint_generatort::add_axioms_for_equals(
   symbol_exprt eq=fresh_boolean("equal");
   typecast_exprt tc_eq(eq, f.type());
 
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
-  string_exprt s2=add_axioms_for_string_expr(args(f, 2)[1]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
+  string_exprt s2=get_string_expr(args(f, 2)[1]);
   typet index_type=s1.length().type();
 
   // We want to write:
@@ -54,9 +56,10 @@ exprt string_constraint_generatort::add_axioms_for_equals(
     binary_relation_exprt(witness, ID_lt, s1.length()),
     binary_relation_exprt(witness, ID_ge, zero));
   and_exprt witnessing(bound_witness, notequal_exprt(s1[witness], s2[witness]));
-  implies_exprt a3(
-    not_exprt(eq),
-    or_exprt(notequal_exprt(s1.length(), s2.length()), witnessing));
+  and_exprt diff_length(
+    notequal_exprt(s1.length(), s2.length()),
+    equal_exprt(witness, from_integer(-1, index_type)));
+  implies_exprt a3(not_exprt(eq), or_exprt(diff_length, witnessing));
   axioms.push_back(a3);
 
   return tc_eq;
@@ -92,8 +95,13 @@ exprt string_constraint_generatort::character_equals_ignore_case(
   // p3 : (is_up2&&'a'-'A'+char2=char1)
   equal_exprt p1(char1, char2);
   minus_exprt diff=minus_exprt(char_a, char_A);
-  and_exprt p2(is_upper_case_1, equal_exprt(plus_exprt(diff, char1), char2));
-  and_exprt p3(is_upper_case_2, equal_exprt(plus_exprt(diff, char2), char1));
+
+  // Overflow is not a problem here because is_upper_case conditions
+  // ensure that we are within a safe range.
+  and_exprt p2(is_upper_case_1,
+               equal_exprt(plus_exprt(diff, char1), char2));
+  and_exprt p3(is_upper_case_2,
+               equal_exprt(plus_exprt(diff, char2), char1));
   return or_exprt(or_exprt(p1, p2), p3);
 }
 
@@ -116,8 +124,8 @@ exprt string_constraint_generatort::add_axioms_for_equals_ignore_case(
 
   symbol_exprt eq=fresh_boolean("equal_ignore_case");
   typecast_exprt tc_eq(eq, f.type());
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
-  string_exprt s2=add_axioms_for_string_expr(args(f, 2)[1]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
+  string_exprt s2=get_string_expr(args(f, 2)[1]);
   typet char_type=to_refined_string_type(s1.type()).get_char_type();
   exprt char_a=constant_char('a', char_type);
   exprt char_A=constant_char('A', char_type);
@@ -174,37 +182,35 @@ Function: string_constraint_generatort::add_axioms_for_hash_code
 exprt string_constraint_generatort::add_axioms_for_hash_code(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
+  string_exprt str=get_string_expr(args(f, 1)[0]);
   typet return_type=f.type();
   typet index_type=str.length().type();
 
-  // initialisation of the missing pool variable
-  std::map<irep_idt, string_exprt>::iterator it;
-  for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
-    if(hash.find(it->second)==hash.end())
-      hash[it->second]=fresh_symbol("hash", return_type);
+  auto pair=hash_code_of_string.insert(
+    std::make_pair(str, fresh_symbol("hash", return_type)));
+  exprt hash=pair.first->second;
 
   // for each string s. either:
   //   c1: hash(str)=hash(s)
   //   c2: |str|!=|s|
-  //   c3: (|str|==|s| &&exists i<|s|. s[i]!=str[i])
+  //   c3: (|str|==|s| && exists i<|s|. s[i]!=str[i])
 
   // WARNING: the specification may be incomplete
-  for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
+  for(auto it : hash_code_of_string)
   {
     symbol_exprt i=fresh_exist_index("index_hash", index_type);
-    equal_exprt c1(hash[it->second], hash[str]);
-    not_exprt c2(equal_exprt(it->second.length(), str.length()));
+    equal_exprt c1(it.second, hash);
+    not_exprt c2(equal_exprt(it.first.length(), str.length()));
     and_exprt c3(
-      equal_exprt(it->second.length(), str.length()),
+      equal_exprt(it.first.length(), str.length()),
       and_exprt(
-        not_exprt(equal_exprt(str[i], it->second[i])),
+        not_exprt(equal_exprt(str[i], it.first[i])),
         and_exprt(
           str.axiom_for_is_strictly_longer_than(i),
           axiom_for_is_positive_index(i))));
     axioms.push_back(or_exprt(c1, or_exprt(c2, c3)));
   }
-  return hash[str];
+  return hash;
 }
 
 /*******************************************************************\
@@ -222,8 +228,8 @@ Function: string_constraint_generatort::add_axioms_for_compare_to
 exprt string_constraint_generatort::add_axioms_for_compare_to(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
-  string_exprt s2=add_axioms_for_string_expr(args(f, 2)[1]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
+  string_exprt s2=get_string_expr(args(f, 2)[1]);
   const typet &return_type=f.type();
   symbol_exprt res=fresh_symbol("compare_to", return_type);
   typet index_type=s1.length().type();
@@ -234,12 +240,12 @@ exprt string_constraint_generatort::add_axioms_for_compare_to(
   // a1 : res==0 => |s1|=|s2|
   // a2 : forall i<|s1|. s1[i]==s2[i]
   // a3 : exists x.
-  // res!=0 ==> x> 0 &&
-  //   ((|s1| <= |s2| &&x<|s1|) || (|s1| >= |s2| &&x<|s2|)
-  //   &&res=s1[x]-s2[x] )
-  // || cond2:
-  //   (|s1|<|s2| &&x=|s1|) || (|s1| > |s2| &&x=|s2|) &&res=|s1|-|s2|)
-  // a4 : forall i<x. res!=0 => s1[i]=s2[i]
+  //        res!=0 ==> x > 0
+  //        && ((|s1| <= |s2| && x<|s1|) || (|s1| >= |s2| &&x<|s2|)
+  //        && res=s1[x]-s2[x] )
+  //     || cond2:
+  //       (|s1|<|s2| &&x=|s1|) || (|s1| > |s2| &&x=|s2|) &&res=|s1|-|s2|)
+  // a4 : forall i'<x. res!=0 => s1[i]=s2[i]
 
   assert(return_type.id()==ID_signedbv);
 
@@ -282,7 +288,9 @@ exprt string_constraint_generatort::add_axioms_for_compare_to(
       or_exprt(cond1, cond2)));
   axioms.push_back(a3);
 
-  string_constraintt a4(i, x, not_exprt(res_null), equal_exprt(s1[i], s2[i]));
+  symbol_exprt i2=fresh_univ_index("QA_compare_to", index_type);
+  string_constraintt a4(
+    i2, x, not_exprt(res_null), equal_exprt(s1[i2], s2[i2]));
   axioms.push_back(a4);
 
   return res;
@@ -304,15 +312,15 @@ Function: string_constraint_generatort::add_axioms_for_intern
 symbol_exprt string_constraint_generatort::add_axioms_for_intern(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
+  string_exprt str=get_string_expr(args(f, 1)[0]);
+  // For now we only enforce content equality and not pointer equality
   const typet &return_type=f.type();
+
   typet index_type=str.length().type();
 
-  // initialisation of the missing pool variable
-  std::map<irep_idt, string_exprt>::iterator it;
-  for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
-    if(pool.find(it->second)==pool.end())
-      pool[it->second]=fresh_symbol("pool", return_type);
+  auto pair=intern_of_string.insert(
+    std::make_pair(str, fresh_symbol("pool", return_type)));
+  symbol_exprt intern=pair.first->second;
 
   // intern(str)=s_0 || s_1 || ...
   // for each string s.
@@ -320,30 +328,30 @@ symbol_exprt string_constraint_generatort::add_axioms_for_intern(
   //    || (|str|==|s| &&exists i<|s|. s[i]!=str[i])
 
   exprt disj=false_exprt();
-  for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
+  for(auto it : intern_of_string)
     disj=or_exprt(
-      disj, equal_exprt(pool[str], symbol_exprt(it->first, return_type)));
+      disj, equal_exprt(intern, it.second));
 
   axioms.push_back(disj);
 
 
   // WARNING: the specification may be incomplete or incorrect
-  for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
-    if(it->second!=str)
+  for(auto it : intern_of_string)
+    if(it.second!=str)
     {
       symbol_exprt i=fresh_exist_index("index_intern", index_type);
       axioms.push_back(
         or_exprt(
-          equal_exprt(pool[it->second], pool[str]),
+          equal_exprt(it.second, intern),
           or_exprt(
-            not_exprt(str.axiom_for_has_same_length_as(it->second)),
+            not_exprt(str.axiom_for_has_same_length_as(it.first)),
             and_exprt(
-              str.axiom_for_has_same_length_as(it->second),
+              str.axiom_for_has_same_length_as(it.first),
               and_exprt(
-                not_exprt(equal_exprt(str[i], it->second[i])),
+                not_exprt(equal_exprt(str[i], it.first[i])),
                 and_exprt(str.axiom_for_is_strictly_longer_than(i),
                           axiom_for_is_positive_index(i)))))));
     }
 
-  return pool[str];
+  return intern;
 }
diff --git a/src/solvers/refinement/string_constraint_generator_concat.cpp b/src/solvers/refinement/string_constraint_generator_concat.cpp
index a7d9c4921c4..eb841cc5b04 100644
--- a/src/solvers/refinement/string_constraint_generator_concat.cpp
+++ b/src/solvers/refinement/string_constraint_generator_concat.cpp
@@ -35,8 +35,7 @@ string_exprt string_constraint_generatort::add_axioms_for_concat(
   // a4 : forall i<|s1|. res[i]=s1[i]
   // a5 : forall i<|s2|. res[i+|s1|]=s2[i]
 
-  exprt a1=res.axiom_for_has_length(
-    plus_exprt(s1.length(), s2.length()));
+  equal_exprt a1(res.length(), plus_exprt_with_overflow_check(s1.length(), s2.length()));
   axioms.push_back(a1);
   axioms.push_back(s1.axiom_for_is_shorter_than(res));
   axioms.push_back(s2.axiom_for_is_shorter_than(res));
@@ -73,8 +72,8 @@ string_exprt string_constraint_generatort::add_axioms_for_concat(
   const function_application_exprt::argumentst &args=f.arguments();
   assert(args.size()==2);
 
-  string_exprt s1=add_axioms_for_string_expr(args[0]);
-  string_exprt s2=add_axioms_for_string_expr(args[1]);
+  string_exprt s1=get_string_expr(args[0]);
+  string_exprt s2=get_string_expr(args[1]);
 
   return add_axioms_for_concat(s1, s2);
 }
@@ -95,7 +94,7 @@ string_exprt string_constraint_generatort::add_axioms_for_concat_int(
   const function_application_exprt &f)
 {
   const refined_string_typet &ref_type=to_refined_string_type(f.type());
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
   string_exprt s2=add_axioms_from_int(
     args(f, 2)[1], MAX_INTEGER_LENGTH, ref_type);
   return add_axioms_for_concat(s1, s2);
@@ -118,7 +117,7 @@ string_exprt string_constraint_generatort::add_axioms_for_concat_long(
   const function_application_exprt &f)
 {
   const refined_string_typet &ref_type=to_refined_string_type(f.type());
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
   string_exprt s2=add_axioms_from_int(args(f, 2)[1], MAX_LONG_LENGTH, ref_type);
   return add_axioms_for_concat(s1, s2);
 }
@@ -138,7 +137,7 @@ Function: string_constraint_generatort::add_axioms_for_concat_bool
 string_exprt string_constraint_generatort::add_axioms_for_concat_bool(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(s1.type());
   string_exprt s2=add_axioms_from_bool(args(f, 2)[1], ref_type);
   return add_axioms_for_concat(s1, s2);
@@ -159,7 +158,7 @@ Function: string_constraint_generatort::add_axioms_for_concat_char
 string_exprt string_constraint_generatort::add_axioms_for_concat_char(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(s1.type());
   string_exprt s2=add_axioms_from_char(args(f, 2)[1], ref_type);
   return add_axioms_for_concat(s1, s2);
@@ -180,9 +179,10 @@ Function: string_constraint_generatort::add_axioms_for_concat_double
 string_exprt string_constraint_generatort::add_axioms_for_concat_double(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
-  string_exprt s2=add_axioms_from_float(
-    args(f, 2)[1], MAX_DOUBLE_LENGTH);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
+  assert(refined_string_typet::is_refined_string_type(f.type()));
+  refined_string_typet ref_type=to_refined_string_type(f.type());
+  string_exprt s2=add_axioms_from_float(args(f, 2)[1], ref_type, true);
   return add_axioms_for_concat(s1, s2);
 }
 
@@ -201,8 +201,10 @@ Function: string_constraint_generatort::add_axioms_for_concat_float
 string_exprt string_constraint_generatort::add_axioms_for_concat_float(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
-  string_exprt s2=add_axioms_from_float(args(f, 2)[1], MAX_FLOAT_LENGTH);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
+  assert(refined_string_typet::is_refined_string_type(f.type()));
+  refined_string_typet ref_type=to_refined_string_type(f.type());
+  string_exprt s2=add_axioms_from_float(args(f, 2)[1], ref_type, false);
   return add_axioms_for_concat(s1, s2);
 }
 
@@ -222,7 +224,7 @@ Function: string_constraint_generatort::add_axioms_for_concat_code_point
 string_exprt string_constraint_generatort::add_axioms_for_concat_code_point(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(s1.type());
   string_exprt s2=add_axioms_for_code_point(args(f, 2)[1], ref_type);
   return add_axioms_for_concat(s1, s2);
diff --git a/src/solvers/refinement/string_constraint_generator_constants.cpp b/src/solvers/refinement/string_constraint_generator_constants.cpp
index 90769747949..2905c6a5f21 100644
--- a/src/solvers/refinement/string_constraint_generator_constants.cpp
+++ b/src/solvers/refinement/string_constraint_generator_constants.cpp
@@ -93,9 +93,13 @@ string_exprt string_constraint_generatort::add_axioms_for_empty_string(
   const function_application_exprt &f)
 {
   assert(f.arguments().empty());
+  assert(refined_string_typet::is_refined_string_type(f.type()));
   const refined_string_typet &ref_type=to_refined_string_type(f.type());
-  string_exprt res=fresh_string(ref_type);
-  axioms.push_back(res.axiom_for_has_length(0));
+  exprt size=from_integer(0, ref_type.get_index_type());
+  const array_typet &content_type=ref_type.get_content_type();
+  array_of_exprt empty_array(
+    from_integer(0, ref_type.get_content_type().subtype()), content_type);
+  string_exprt res(size, empty_array, ref_type);
   return res;
 }
 
@@ -132,7 +136,8 @@ string_exprt string_constraint_generatort::add_axioms_from_literal(
   else
   {
     // Java string constant
-    assert(refined_string_typet::is_unrefined_string_type(arg.type()));
+    assert(false); // TODO: Check if used. On the contrary, discard else.
+    assert(arg.id()==ID_symbol);
     const exprt &s=arg.op0();
 
     // It seems the value of the string is lost,
diff --git a/src/solvers/refinement/string_constraint_generator_indexof.cpp b/src/solvers/refinement/string_constraint_generator_indexof.cpp
index 93db048458b..d799091a573 100644
--- a/src/solvers/refinement/string_constraint_generator_indexof.cpp
+++ b/src/solvers/refinement/string_constraint_generator_indexof.cpp
@@ -92,15 +92,16 @@ exprt string_constraint_generatort::add_axioms_for_index_of_string(
   symbol_exprt contains=fresh_boolean("contains_substring");
 
   // We add axioms:
-  // a1 : contains => |substring|>=offset>=from_index
+  // a1 : contains => |str|-|substring|>=offset>=from_index
   // a2 : !contains => offset=-1
-  // a3 : forall 0 <= witness<substring.length.
-  //   contains => str[witness+offset]=substring[witness]
+  // a3 : forall 0<=witness<|substring|.
+  //        contains => str[witness+offset]=substring[witness]
 
   implies_exprt a1(
     contains,
     and_exprt(
-      str.axiom_for_is_longer_than(plus_exprt(substring.length(), offset)),
+      str.axiom_for_is_longer_than(plus_exprt_with_overflow_check(
+        substring.length(), offset)),
       binary_relation_exprt(offset, ID_ge, from_index)));
   axioms.push_back(a1);
 
@@ -138,7 +139,8 @@ exprt string_constraint_generatort::add_axioms_for_last_index_of_string(
   implies_exprt a1(
     contains,
     and_exprt(
-      str.axiom_for_is_longer_than(plus_exprt(substring.length(), offset)),
+      str.axiom_for_is_longer_than(
+        plus_exprt_with_overflow_check(substring.length(), offset)),
       binary_relation_exprt(offset, ID_le, from_index)));
   axioms.push_back(a1);
 
@@ -173,7 +175,7 @@ exprt string_constraint_generatort::add_axioms_for_index_of(
   const function_application_exprt &f)
 {
   const function_application_exprt::argumentst &args=f.arguments();
-  string_exprt str=add_axioms_for_string_expr(args[0]);
+  string_exprt str=get_string_expr(args[0]);
   const exprt &c=args[1];
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   assert(f.type()==ref_type.get_index_type());
@@ -186,14 +188,17 @@ exprt string_constraint_generatort::add_axioms_for_index_of(
   else
     assert(false);
 
-  if(refined_string_typet::is_java_string_pointer_type(c.type()))
+  if(c.type().id()==ID_unsignedbv || c.type().id()==ID_signedbv)
   {
-    string_exprt sub=add_axioms_for_string_expr(c);
-    return add_axioms_for_index_of_string(str, sub, from_index);
-  }
-  else
     return add_axioms_for_index_of(
       str, typecast_exprt(c, ref_type.get_char_type()), from_index);
+  }
+  else
+  {
+    assert(refined_string_typet::is_refined_string_type(c.type()));
+    string_exprt sub=get_string_expr(c);
+    return add_axioms_for_index_of_string(str, sub, from_index);
+  }
 }
 
 exprt string_constraint_generatort::add_axioms_for_last_index_of(
@@ -213,7 +218,7 @@ exprt string_constraint_generatort::add_axioms_for_last_index_of(
 
   exprt index1=from_integer(1, index_type);
   exprt minus1=from_integer(-1, index_type);
-  exprt from_index_plus_one=plus_exprt(from_index, index1);
+  exprt from_index_plus_one=plus_exprt_with_overflow_check(from_index, index1);
   and_exprt a1(
     binary_relation_exprt(index, ID_ge, minus1),
     binary_relation_exprt(index, ID_lt, from_index_plus_one));
@@ -267,7 +272,7 @@ exprt string_constraint_generatort::add_axioms_for_last_index_of(
   const function_application_exprt &f)
 {
   const function_application_exprt::argumentst &args=f.arguments();
-  string_exprt str=add_axioms_for_string_expr(args[0]);
+  string_exprt str=get_string_expr(args[0]);
   exprt c=args[1];
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   exprt from_index;
@@ -280,12 +285,14 @@ exprt string_constraint_generatort::add_axioms_for_last_index_of(
   else
     assert(false);
 
-  if(refined_string_typet::is_java_string_pointer_type(c.type()))
+  if(c.type().id()==ID_unsignedbv || c.type().id()==ID_signedbv)
   {
-    string_exprt sub=add_axioms_for_string_expr(c);
-    return add_axioms_for_last_index_of_string(str, sub, from_index);
-  }
-  else
     return add_axioms_for_last_index_of(
       str, typecast_exprt(c, ref_type.get_char_type()), from_index);
+  }
+  else
+  {
+    string_exprt sub=get_string_expr(c);
+    return add_axioms_for_last_index_of_string(str, sub, from_index);
+  }
 }
diff --git a/src/solvers/refinement/string_constraint_generator_insert.cpp b/src/solvers/refinement/string_constraint_generator_insert.cpp
index 6a080a5dc6c..cd5f4376a93 100644
--- a/src/solvers/refinement/string_constraint_generator_insert.cpp
+++ b/src/solvers/refinement/string_constraint_generator_insert.cpp
@@ -48,8 +48,8 @@ Function: string_constraint_generatort::add_axioms_for_insert
 string_exprt string_constraint_generatort::add_axioms_for_insert(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
-  string_exprt s2=add_axioms_for_string_expr(args(f, 3)[2]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
+  string_exprt s2=get_string_expr(args(f, 3)[2]);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
 }
 
@@ -70,7 +70,7 @@ string_exprt string_constraint_generatort::add_axioms_for_insert_int(
   const function_application_exprt &f)
 {
   const refined_string_typet &ref_type=to_refined_string_type(f.type());
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
   string_exprt s2=add_axioms_from_int(
     args(f, 3)[2], MAX_INTEGER_LENGTH, ref_type);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
@@ -93,7 +93,7 @@ string_exprt string_constraint_generatort::add_axioms_for_insert_long(
   const function_application_exprt &f)
 {
   const refined_string_typet &ref_type=to_refined_string_type(f.type());
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
   string_exprt s2=add_axioms_from_int(args(f, 3)[2], MAX_LONG_LENGTH, ref_type);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
 }
@@ -115,7 +115,7 @@ string_exprt string_constraint_generatort::add_axioms_for_insert_bool(
   const function_application_exprt &f)
 {
   const refined_string_typet &ref_type=to_refined_string_type(f.type());
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
   string_exprt s2=add_axioms_from_bool(args(f, 3)[2], ref_type);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
 }
@@ -136,7 +136,7 @@ Function: string_constraint_generatort::add_axioms_for_insert_char
 string_exprt string_constraint_generatort::add_axioms_for_insert_char(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(s1.type());
   string_exprt s2=add_axioms_from_char(args(f, 3)[2], ref_type);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
@@ -158,8 +158,9 @@ Function: string_constraint_generatort::add_axioms_for_insert_double
 string_exprt string_constraint_generatort::add_axioms_for_insert_double(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
-  string_exprt s2=add_axioms_from_float(args(f, 3)[2]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
+  const refined_string_typet &ref_type=to_refined_string_type(s1.type());
+  string_exprt s2=add_axioms_from_float(args(f, 3)[2], ref_type, true);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
 }
 
@@ -179,8 +180,9 @@ Function: string_constraint_generatort::add_axioms_for_insert_float
 string_exprt string_constraint_generatort::add_axioms_for_insert_float(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 3)[0]);
-  string_exprt s2=add_axioms_from_float(args(f, 3)[2]);
+  string_exprt s1=get_string_expr(args(f, 3)[0]);
+  const refined_string_typet &ref_type=to_refined_string_type(s1.type());
+  string_exprt s2=add_axioms_from_float(args(f, 3)[2], ref_type, false);
   return add_axioms_for_insert(s1, s2, args(f, 3)[1]);
 }
 
@@ -216,7 +218,7 @@ string_exprt string_constraint_generatort::add_axioms_for_insert_char_array(
     offset=from_integer(0, count.type());
   }
 
-  string_exprt str=add_axioms_for_string_expr(f.arguments()[0]);
+  string_exprt str=get_string_expr(f.arguments()[0]);
   const exprt &length=f.arguments()[2];
   const exprt &data=f.arguments()[3];
   string_exprt arr=add_axioms_from_char_array(
diff --git a/src/solvers/refinement/string_constraint_generator_main.cpp b/src/solvers/refinement/string_constraint_generator_main.cpp
index 5a269e5ad3b..1b94d05a462 100644
--- a/src/solvers/refinement/string_constraint_generator_main.cpp
+++ b/src/solvers/refinement/string_constraint_generator_main.cpp
@@ -16,6 +16,7 @@ Author: Romain Brenguier, romain.brenguier@diffblue.com
 #include <util/arith_tools.h>
 #include <util/pointer_predicates.h>
 #include <util/ssa_expr.h>
+#include <iostream>
 
 unsigned string_constraint_generatort::next_symbol_id=1;
 
@@ -122,6 +123,42 @@ symbol_exprt string_constraint_generatort::fresh_boolean(
 
 /*******************************************************************\
 
+Function: string_constraint_generatort::plus_exprt_with_overflow_check
+
+ Inputs:
+  op1 - First term of the sum
+  op2 - Second term of the sum
+
+ Outputs: A plus expression representing the sum of the arguments
+
+ Purpose: Create a plus expression while adding extra constraints to
+          axioms in order to prevent overflows.
+
+\*******************************************************************/
+plus_exprt string_constraint_generatort::plus_exprt_with_overflow_check(
+  const exprt &op1, const exprt &op2)
+{
+  plus_exprt sum(plus_exprt(op1, op2));
+
+  exprt zero=from_integer(0, op1.type());
+
+  binary_relation_exprt neg1(op1, ID_lt, zero);
+  binary_relation_exprt neg2(op2, ID_lt, zero);
+  binary_relation_exprt neg_sum(sum, ID_lt, zero);
+
+  // We prevent overflows by adding the following constraint:
+  // If the signs of the two operands are the same, then the sign of the sum
+  // should also be the same.
+  implies_exprt no_overflow(equal_exprt(neg1, neg2),
+                            equal_exprt(neg1, neg_sum));
+
+  axioms.push_back(no_overflow);
+
+  return sum;
+}
+
+/*******************************************************************\
+
 Function: string_constraint_generatort::fresh_string
 
   Inputs: a type for string
@@ -136,67 +173,157 @@ Function: string_constraint_generatort::fresh_string
 string_exprt string_constraint_generatort::fresh_string(
   const refined_string_typet &type)
 {
-  symbol_exprt length=
-    fresh_symbol("string_length", type.get_index_type());
+  symbol_exprt length=fresh_symbol("string_length", type.get_index_type());
   symbol_exprt content=fresh_symbol("string_content", type.get_content_type());
-  return string_exprt(length, content, type);
+  string_exprt str(length, content, type);
+  created_strings.insert(str);
+  return str;
+}
+
+/*******************************************************************\
+
+Function: string_constraint_generatort::get_string_expr
+
+  Inputs: an expression of refined string type
+
+ Outputs: a string expression
+
+ Purpose: casts an expression to a string expression, or fetches the
+          actual string_exprt in the case of a symbol.
+
+\*******************************************************************/
+
+string_exprt string_constraint_generatort::get_string_expr(const exprt &expr)
+{
+  assert(refined_string_typet::is_refined_string_type(expr.type()));
+
+  if(expr.id()==ID_symbol)
+  {
+    return find_or_add_string_of_symbol(
+      to_symbol_expr(expr),
+      to_refined_string_type(expr.type()));
+  }
+  else
+  {
+    return to_string_expr(expr);
+  }
+}
+
+string_exprt string_constraint_generatort::convert_java_string_to_string_exprt(
+    const exprt &jls)
+{
+  assert(get_mode()==ID_java);
+  assert(jls.id()==ID_struct);
+
+  exprt length(to_struct_expr(jls).op1());
+  // TODO: Add assertion on the type.
+  // assert(length.type()==refined_string_typet::index_type());
+  exprt java_content(to_struct_expr(jls).op2());
+  if(java_content.id()==ID_address_of)
+  {
+    java_content=to_address_of_expr(java_content).object();
+  }
+  else
+  {
+    java_content=dereference_exprt(java_content, java_content.type());
+  }
+
+  refined_string_typet type(java_int_type(), java_char_type());
+
+  return string_exprt(length, java_content, type);
+}
+
+/*******************************************************************\
+
+Function: string_constraint_generatort::add_default_constraints
+
+  Inputs:
+    s - a string expression
+
+ Outputs: a string expression that is linked to the argument through
+          axioms that are added to the list
+
+ Purpose: adds standard axioms about the length of the string and
+          its content:
+          * its length should be positive
+          * it should not exceed max_string_length
+          * if force_printable_characters is true then all characters
+            should belong to the range of ASCII characters between ' ' and '~'
+
+
+\*******************************************************************/
+
+void string_constraint_generatort::add_default_axioms(
+  const string_exprt &s)
+{
+  s.axiom_for_is_longer_than(from_integer(0, s.length().type()));
+  if(max_string_length>=0)
+    axioms.push_back(s.axiom_for_is_shorter_than(max_string_length));
+
+  if(force_printable_characters)
+  {
+    symbol_exprt qvar=fresh_univ_index("printable", s.length().type());
+    exprt chr=s[qvar];
+    and_exprt printable(
+      binary_relation_exprt(chr, ID_ge, from_integer(' ', chr.type())),
+      binary_relation_exprt(chr, ID_le, from_integer('~', chr.type())));
+    string_constraintt sc(qvar, s.length(), printable);
+    axioms.push_back(sc);
+  }
 }
 
 /*******************************************************************\
 
-Function: string_constraint_generatort::add_axioms_for_string_expr
+Function: string_constraint_generatort::add_axioms_for_refined_string
 
-  Inputs: an expression of type string
+  Inputs: an expression of refined string type
 
  Outputs: a string expression that is linked to the argument through
           axioms that are added to the list
 
- Purpose: obtain a refined string expression corresponding to string
-          variable of string function call
+ Purpose: obtain a refined string expression corresponding to a expression
+          of type string
 
 \*******************************************************************/
 
-string_exprt string_constraint_generatort::add_axioms_for_string_expr(
-  const exprt &unrefined_string)
+string_exprt string_constraint_generatort::add_axioms_for_refined_string(
+  const exprt &string)
 {
-  string_exprt s;
+  assert(refined_string_typet::is_refined_string_type(string.type()));
+  refined_string_typet type=to_refined_string_type(string.type());
 
-  if(unrefined_string.id()==ID_function_application)
+  // Function applications should have been removed before
+  assert(string.id()!=ID_function_application);
+
+  if(string.id()==ID_symbol)
   {
-    exprt res=add_axioms_for_function_application(
-      to_function_application_expr(unrefined_string));
-    s=to_string_expr(res);
+    const symbol_exprt &sym=to_symbol_expr(string);
+    string_exprt s=find_or_add_string_of_symbol(sym, type);
+    add_default_axioms(s);
+    return s;
   }
-  else if(unrefined_string.id()==ID_symbol)
-    s=find_or_add_string_of_symbol(to_symbol_expr(unrefined_string));
-  else if(unrefined_string.id()==ID_address_of)
+  else if(string.id()==ID_nondet_symbol)
   {
-    assert(unrefined_string.op0().id()==ID_symbol);
-    s=find_or_add_string_of_symbol(to_symbol_expr(unrefined_string.op0()));
+    string_exprt s=fresh_string(type);
+    add_default_axioms(s);
+    return s;
   }
-  else if(unrefined_string.id()==ID_if)
-    s=add_axioms_for_if(to_if_expr(unrefined_string));
-  else if(unrefined_string.id()==ID_nondet_symbol ||
-          unrefined_string.id()==ID_struct)
+  else if(string.id()==ID_if)
   {
-    // TODO: for now we ignore non deterministic symbols and struct
+    return add_axioms_for_if(to_if_expr(string));
   }
-  else if(unrefined_string.id()==ID_typecast)
+  else if(string.id()==ID_struct)
   {
-    exprt arg=to_typecast_expr(unrefined_string).op();
-    exprt res=add_axioms_for_string_expr(arg);
-    s=to_string_expr(res);
+    const string_exprt &s=to_string_expr(string);
+    add_default_axioms(s);
+    return s;
   }
   else
   {
-    throw "add_axioms_for_string_expr:\n"+unrefined_string.pretty()+
+    throw "add_axioms_for_refined_string:\n"+string.pretty()+
       "\nwhich is not a function application, "+
-      "a symbol or an if expression";
+      "a symbol, a struct or an if expression";
   }
-
-  axioms.push_back(
-    s.axiom_for_is_longer_than(from_integer(0, s.length().type())));
-  return s;
 }
 
 /*******************************************************************\
@@ -215,11 +342,11 @@ string_exprt string_constraint_generatort::add_axioms_for_if(
   const if_exprt &expr)
 {
   assert(
-    refined_string_typet::is_unrefined_string_type(expr.true_case().type()));
-  string_exprt t=add_axioms_for_string_expr(expr.true_case());
+    refined_string_typet::is_refined_string_type(expr.true_case().type()));
+  string_exprt t=get_string_expr(expr.true_case());
   assert(
-    refined_string_typet::is_unrefined_string_type(expr.false_case().type()));
-  string_exprt f=add_axioms_for_string_expr(expr.false_case());
+    refined_string_typet::is_refined_string_type(expr.false_case().type()));
+  string_exprt f=get_string_expr(expr.false_case());
   const refined_string_typet &ref_type=to_refined_string_type(t.type());
   const typet &index_type=ref_type.get_index_type();
   string_exprt res=fresh_string(ref_type);
@@ -246,7 +373,7 @@ Function: string_constraint_generatort::find_or_add_string_of_symbol
 
  Outputs: a string expression
 
- Purpose: if a symbol represent a string is present in the symbol_to_string
+ Purpose: if a symbol representing a string is present in the symbol_to_string
           table, returns the corresponding string, if the symbol is not yet
           present, creates a new string with the correct type depending on
           whether the mode is java or c, adds it to the table and returns it.
@@ -254,12 +381,11 @@ Function: string_constraint_generatort::find_or_add_string_of_symbol
 \*******************************************************************/
 
 string_exprt string_constraint_generatort::find_or_add_string_of_symbol(
-  const symbol_exprt &sym)
+  const symbol_exprt &sym, const refined_string_typet &ref_type)
 {
   irep_idt id=sym.get_identifier();
-  const refined_string_typet &ref_type=to_refined_string_type(sym.type());
   string_exprt str=fresh_string(ref_type);
-  auto entry=symbol_to_string.insert(std::make_pair(id, str));
+  auto entry=unresolved_symbols.insert(std::make_pair(id, str));
   return entry.first->second;
 }
 
@@ -286,125 +412,180 @@ exprt string_constraint_generatort::add_axioms_for_function_application(
   const irep_idt &id=is_ssa_expr(name)?to_ssa_expr(name).get_object_name():
     to_symbol_expr(name).get_identifier();
 
+  std::string str_id(id.c_str());
+
+  size_t pos=str_id.find("func_length");
+  if(pos!=std::string::npos)
+  {
+    function_application_exprt new_expr(expr);
+    // TODO: This part needs some improvement.
+    // Stripping the symbol name is not a very robust process.
+    new_expr.function() = symbol_exprt(str_id.substr(0, pos+4));
+    assert(get_mode()==ID_java);
+    new_expr.type() = refined_string_typet(java_int_type(), java_char_type());
+
+    auto res_it=function_application_cache.insert(std::make_pair(new_expr,
+                                                                 nil_exprt()));
+    if(res_it.second)
+    {
+      string_exprt res=to_string_expr(
+        add_axioms_for_function_application(new_expr));
+      res_it.first->second=res;
+      return res.length();
+    }
+    else
+      return to_string_expr(res_it.first->second).length();
+  }
+
+  pos = str_id.find("func_data");
+  if(pos!=std::string::npos)
+  {
+    function_application_exprt new_expr(expr);
+    new_expr.function() = symbol_exprt(str_id.substr(0, pos+4));
+    new_expr.type() = refined_string_typet(java_int_type(), java_char_type());
+
+    auto res_it=function_application_cache.insert(std::make_pair(new_expr,
+                                                                 nil_exprt()));
+    if(res_it.second)
+    {
+      string_exprt res=to_string_expr(
+        add_axioms_for_function_application(new_expr));
+      res_it.first->second=res;
+      return res.content();
+    }
+    else
+      return to_string_expr(res_it.first->second).content();
+  }
+
   // TODO: improve efficiency of this test by either ordering test by frequency
   // or using a map
 
+  auto res_it=function_application_cache.find(expr);
+  if(res_it!=function_application_cache.end() && res_it->second!=nil_exprt())
+    return res_it->second;
+
+  exprt res;
+
   if(id==ID_cprover_char_literal_func)
-    return add_axioms_for_char_literal(expr);
+    res=add_axioms_for_char_literal(expr);
   else if(id==ID_cprover_string_length_func)
-    return add_axioms_for_length(expr);
+    res=add_axioms_for_length(expr);
   else if(id==ID_cprover_string_equal_func)
-    return add_axioms_for_equals(expr);
+    res=add_axioms_for_equals(expr);
   else if(id==ID_cprover_string_equals_ignore_case_func)
-    return add_axioms_for_equals_ignore_case(expr);
+    res=add_axioms_for_equals_ignore_case(expr);
   else if(id==ID_cprover_string_is_empty_func)
-    return add_axioms_for_is_empty(expr);
+    res=add_axioms_for_is_empty(expr);
   else if(id==ID_cprover_string_char_at_func)
-    return add_axioms_for_char_at(expr);
+    res=add_axioms_for_char_at(expr);
   else if(id==ID_cprover_string_is_prefix_func)
-    return add_axioms_for_is_prefix(expr);
+    res=add_axioms_for_is_prefix(expr);
   else if(id==ID_cprover_string_is_suffix_func)
-    return add_axioms_for_is_suffix(expr);
+    res=add_axioms_for_is_suffix(expr);
   else if(id==ID_cprover_string_startswith_func)
-    return add_axioms_for_is_prefix(expr, true);
+    res=add_axioms_for_is_prefix(expr, true);
   else if(id==ID_cprover_string_endswith_func)
-    return add_axioms_for_is_suffix(expr, true);
+    res=add_axioms_for_is_suffix(expr, true);
   else if(id==ID_cprover_string_contains_func)
-    return add_axioms_for_contains(expr);
+    res=add_axioms_for_contains(expr);
   else if(id==ID_cprover_string_hash_code_func)
-    return add_axioms_for_hash_code(expr);
+    res=add_axioms_for_hash_code(expr);
   else if(id==ID_cprover_string_index_of_func)
-    return add_axioms_for_index_of(expr);
+    res=add_axioms_for_index_of(expr);
   else if(id==ID_cprover_string_last_index_of_func)
-    return add_axioms_for_last_index_of(expr);
+    res=add_axioms_for_last_index_of(expr);
   else if(id==ID_cprover_string_parse_int_func)
-    return add_axioms_for_parse_int(expr);
+    res=add_axioms_for_parse_int(expr);
   else if(id==ID_cprover_string_to_char_array_func)
-    return add_axioms_for_to_char_array(expr);
+    res=add_axioms_for_to_char_array(expr);
   else if(id==ID_cprover_string_code_point_at_func)
-    return add_axioms_for_code_point_at(expr);
+    res=add_axioms_for_code_point_at(expr);
   else if(id==ID_cprover_string_code_point_before_func)
-    return add_axioms_for_code_point_before(expr);
+    res=add_axioms_for_code_point_before(expr);
   else if(id==ID_cprover_string_code_point_count_func)
-    return add_axioms_for_code_point_count(expr);
+    res=add_axioms_for_code_point_count(expr);
   else if(id==ID_cprover_string_offset_by_code_point_func)
-    return add_axioms_for_offset_by_code_point(expr);
+    res=add_axioms_for_offset_by_code_point(expr);
   else if(id==ID_cprover_string_compare_to_func)
-    return add_axioms_for_compare_to(expr);
+    res=add_axioms_for_compare_to(expr);
   else if(id==ID_cprover_string_literal_func)
-    return add_axioms_from_literal(expr);
+    res=add_axioms_from_literal(expr);
   else if(id==ID_cprover_string_concat_func)
-    return add_axioms_for_concat(expr);
+    res=add_axioms_for_concat(expr);
   else if(id==ID_cprover_string_concat_int_func)
-    return add_axioms_for_concat_int(expr);
+    res=add_axioms_for_concat_int(expr);
   else if(id==ID_cprover_string_concat_long_func)
-    return add_axioms_for_concat_long(expr);
+    res=add_axioms_for_concat_long(expr);
   else if(id==ID_cprover_string_concat_bool_func)
-      return add_axioms_for_concat_bool(expr);
+      res=add_axioms_for_concat_bool(expr);
   else if(id==ID_cprover_string_concat_char_func)
-    return add_axioms_for_concat_char(expr);
+    res=add_axioms_for_concat_char(expr);
   else if(id==ID_cprover_string_concat_double_func)
-    return add_axioms_for_concat_double(expr);
+    res=add_axioms_for_concat_double(expr);
   else if(id==ID_cprover_string_concat_float_func)
-    return add_axioms_for_concat_float(expr);
+    res=add_axioms_for_concat_float(expr);
   else if(id==ID_cprover_string_concat_code_point_func)
-    return add_axioms_for_concat_code_point(expr);
+    res=add_axioms_for_concat_code_point(expr);
   else if(id==ID_cprover_string_insert_func)
-    return add_axioms_for_insert(expr);
+    res=add_axioms_for_insert(expr);
   else if(id==ID_cprover_string_insert_int_func)
-    return add_axioms_for_insert_int(expr);
+    res=add_axioms_for_insert_int(expr);
   else if(id==ID_cprover_string_insert_long_func)
-    return add_axioms_for_insert_long(expr);
+    res=add_axioms_for_insert_long(expr);
   else if(id==ID_cprover_string_insert_bool_func)
-    return add_axioms_for_insert_bool(expr);
+    res=add_axioms_for_insert_bool(expr);
   else if(id==ID_cprover_string_insert_char_func)
-    return add_axioms_for_insert_char(expr);
+    res=add_axioms_for_insert_char(expr);
   else if(id==ID_cprover_string_insert_double_func)
-    return add_axioms_for_insert_double(expr);
+    res=add_axioms_for_insert_double(expr);
   else if(id==ID_cprover_string_insert_float_func)
-    return add_axioms_for_insert_float(expr);
+    res=add_axioms_for_insert_float(expr);
+#if 0
   else if(id==ID_cprover_string_insert_char_array_func)
-    return add_axioms_for_insert_char_array(expr);
+    res=add_axioms_for_insert_char_array(expr);
+#endif
   else if(id==ID_cprover_string_substring_func)
-    return add_axioms_for_substring(expr);
+    res=add_axioms_for_substring(expr);
   else if(id==ID_cprover_string_trim_func)
-    return add_axioms_for_trim(expr);
+    res=add_axioms_for_trim(expr);
   else if(id==ID_cprover_string_to_lower_case_func)
-    return add_axioms_for_to_lower_case(expr);
+    res=add_axioms_for_to_lower_case(expr);
   else if(id==ID_cprover_string_to_upper_case_func)
-    return add_axioms_for_to_upper_case(expr);
+    res=add_axioms_for_to_upper_case(expr);
   else if(id==ID_cprover_string_char_set_func)
-    return add_axioms_for_char_set(expr);
+    res=add_axioms_for_char_set(expr);
   else if(id==ID_cprover_string_value_of_func)
-    return add_axioms_for_value_of(expr);
+    res=add_axioms_for_value_of(expr);
   else if(id==ID_cprover_string_empty_string_func)
-    return add_axioms_for_empty_string(expr);
+    res=add_axioms_for_empty_string(expr);
   else if(id==ID_cprover_string_copy_func)
-    return add_axioms_for_copy(expr);
+    res=add_axioms_for_copy(expr);
   else if(id==ID_cprover_string_of_int_func)
-    return add_axioms_from_int(expr);
+    res=add_axioms_from_int(expr);
   else if(id==ID_cprover_string_of_int_hex_func)
-    return add_axioms_from_int_hex(expr);
+    res=add_axioms_from_int_hex(expr);
   else if(id==ID_cprover_string_of_float_func)
-    return add_axioms_from_float(expr);
+    res=add_axioms_from_float(expr);
   else if(id==ID_cprover_string_of_double_func)
-    return add_axioms_from_double(expr);
+    res=add_axioms_from_double(expr);
   else if(id==ID_cprover_string_of_long_func)
-    return add_axioms_from_long(expr);
+    res=add_axioms_from_long(expr);
   else if(id==ID_cprover_string_of_bool_func)
-    return add_axioms_from_bool(expr);
+    res=add_axioms_from_bool(expr);
   else if(id==ID_cprover_string_of_char_func)
-    return add_axioms_from_char(expr);
-  else if(id==ID_cprover_string_of_char_array_func)
-    return add_axioms_from_char_array(expr);
+    res=add_axioms_from_char(expr);
   else if(id==ID_cprover_string_set_length_func)
-    return add_axioms_for_set_length(expr);
+    res=add_axioms_for_set_length(expr);
   else if(id==ID_cprover_string_delete_func)
-    return add_axioms_for_delete(expr);
+    res=add_axioms_for_delete(expr);
   else if(id==ID_cprover_string_delete_char_at_func)
-    return add_axioms_for_delete_char_at(expr);
+    res=add_axioms_for_delete_char_at(expr);
   else if(id==ID_cprover_string_replace_func)
-    return add_axioms_for_replace(expr);
+    res=add_axioms_for_replace(expr);
+  else if(id==ID_cprover_string_intern_func)
+    res=add_axioms_for_intern(expr);
+  else if(id==ID_cprover_string_array_of_char_pointer_func)
+    res=add_axioms_for_char_pointer(expr);
   else
   {
     std::string msg(
@@ -412,13 +593,16 @@ exprt string_constraint_generatort::add_axioms_for_function_application(
     msg+=id2string(id);
     throw msg;
   }
+  function_application_cache[expr]=res;
+  return res;
 }
 
 /*******************************************************************\
 
 Function: string_constraint_generatort::add_axioms_for_copy
 
-  Inputs: function application with one argument, which is a string
+  Inputs: function application with one argument, which is a string,
+          or three arguments: string, integer offset and count
 
  Outputs: a new string expression
 
@@ -430,20 +614,20 @@ Function: string_constraint_generatort::add_axioms_for_copy
 string_exprt string_constraint_generatort::add_axioms_for_copy(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 1)[0]);
-  const refined_string_typet &ref_type=to_refined_string_type(s1.type());
-  string_exprt res=fresh_string(ref_type);
-
-  // We add axioms:
-  // a1 : |res|=|s1|
-  // a2 : forall i<|s1|. s1[i]=res[i]
-
-  axioms.push_back(res.axiom_for_has_same_length_as(s1));
-
-  symbol_exprt idx=fresh_univ_index("QA_index_copy", ref_type.get_index_type());
-  string_constraintt a2(idx, s1.length(), equal_exprt(s1[idx], res[idx]));
-  axioms.push_back(a2);
-  return res;
+  const auto &args=f.arguments();
+  if(args.size()==1)
+  {
+    string_exprt s1=get_string_expr(args[0]);
+    return s1;
+  }
+  else
+  {
+    assert(args.size()==3);
+    string_exprt s1=get_string_expr(args[0]);
+    exprt offset=args[1];
+    exprt count=args[2];
+    return add_axioms_for_substring(s1, offset, plus_exprt(offset, count));
+  }
 }
 
 /*******************************************************************\
@@ -473,6 +657,28 @@ string_exprt string_constraint_generatort::add_axioms_for_java_char_array(
 
 /*******************************************************************\
 
+Function: string_constraint_generatort::add_axioms_for_char_pointer
+
+  Inputs: an expression of type char
+
+ Outputs: an array expression
+
+ Purpose: for an expression of the form `array[0]` returns `array`
+
+\*******************************************************************/
+
+exprt string_constraint_generatort::add_axioms_for_char_pointer(
+  const function_application_exprt &fun)
+{
+  exprt char_pointer=args(fun, 1)[0];
+  if(char_pointer.id()==ID_index)
+    return char_pointer.op0();
+  // TODO: we do not know what to do in the other cases
+  assert(false);
+}
+
+/*******************************************************************\
+
 Function: string_constraint_generatort::add_axioms_for_length
 
   Inputs: function application with one string argument
@@ -486,7 +692,7 @@ Function: string_constraint_generatort::add_axioms_for_length
 exprt string_constraint_generatort::add_axioms_for_length(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
+  string_exprt str=get_string_expr(args(f, 1)[0]);
   return str.length();
 }
 
@@ -511,6 +717,7 @@ string_exprt string_constraint_generatort::add_axioms_from_char_array(
   const exprt &offset,
   const exprt &count)
 {
+  assert(false); // deprecated, we should use add_axioms_for_substring instead
   const typet &char_type=to_array_type(data.type()).subtype();
   const typet &index_type=length.type();
   refined_string_typet ref_type(index_type, char_type);
@@ -523,7 +730,7 @@ string_exprt string_constraint_generatort::add_axioms_from_char_array(
   symbol_exprt qvar=fresh_univ_index("QA_string_of_char_array", index_type);
   exprt char_in_tab=data;
   assert(char_in_tab.id()==ID_index);
-  char_in_tab.op1()=plus_exprt(qvar, offset);
+  char_in_tab.op1()=plus_exprt_with_overflow_check(qvar, offset);
 
   string_constraintt a1(qvar, count, equal_exprt(str[qvar], char_in_tab));
   axioms.push_back(a1);
@@ -549,6 +756,7 @@ Function: string_constraint_generatort::add_axioms_from_char_array
 string_exprt string_constraint_generatort::add_axioms_from_char_array(
   const function_application_exprt &f)
 {
+  assert(false); // deprecated, we should use add_axioms_for_substring instead
   exprt offset;
   exprt count;
   if(f.arguments().size()==4)
@@ -638,7 +846,7 @@ Function: string_constraint_generatort::add_axioms_for_char_at
 exprt string_constraint_generatort::add_axioms_for_char_at(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt str=get_string_expr(args(f, 2)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   symbol_exprt char_sym=fresh_symbol("char", ref_type.get_char_type());
   axioms.push_back(equal_exprt(char_sym, str[args(f, 2)[1]]));
@@ -660,26 +868,6 @@ Function: string_constraint_generatort::add_axioms_for_to_char_array
 exprt string_constraint_generatort::add_axioms_for_to_char_array(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
+  string_exprt str=get_string_expr(args(f, 1)[0]);
   return str.content();
 }
-
-/*******************************************************************\
-
-Function: string_constraint_generatort::set_string_symbol_equal_to_expr
-
-  Inputs: a symbol and a string
-
- Purpose: add a correspondence to make sure the symbol points to the
-          same string as the second argument
-
-\*******************************************************************/
-
-void string_constraint_generatort::set_string_symbol_equal_to_expr(
-  const symbol_exprt &sym, const exprt &str)
-{
-  if(str.id()==ID_symbol)
-    assign_to_symbol(sym, find_or_add_string_of_symbol(to_symbol_expr(str)));
-  else
-    assign_to_symbol(sym, add_axioms_for_string_expr(str));
-}
diff --git a/src/solvers/refinement/string_constraint_generator_testing.cpp b/src/solvers/refinement/string_constraint_generator_testing.cpp
index 8b1c7bca9d4..2a08b021070 100644
--- a/src/solvers/refinement/string_constraint_generator_testing.cpp
+++ b/src/solvers/refinement/string_constraint_generator_testing.cpp
@@ -31,15 +31,15 @@ exprt string_constraint_generatort::add_axioms_for_is_prefix(
 
   // We add axioms:
   // a1 : isprefix => |str| >= |prefix|+offset
-  // a2 : forall 0<=qvar<prefix.length. isprefix =>
-  //   s0[witness+offset]=s2[witness]
-  // a3 : !isprefix => |str| < |prefix|+offset
-  //   || (|str| >= |prefix|+offset &&0<=witness<|prefix|
-  //     &&str[witness+ofsset]!=prefix[witness])
+  // a2 : forall 0<=qvar<|prefix|. isprefix => s0[witness+offset]=s2[witness]
+  // a3 : !isprefix =>
+  //        |str|<|prefix|+offset ||
+  //        (0<=witness<|prefix| && str[witness+offset]!=prefix[witness])
 
   implies_exprt a1(
     isprefix,
-    str.axiom_for_is_longer_than(plus_exprt(prefix.length(), offset)));
+    str.axiom_for_is_longer_than(plus_exprt_with_overflow_check(
+      prefix.length(), offset)));
   axioms.push_back(a1);
 
   symbol_exprt qvar=fresh_univ_index("QA_isprefix", index_type);
@@ -47,7 +47,8 @@ exprt string_constraint_generatort::add_axioms_for_is_prefix(
     qvar,
     prefix.length(),
     isprefix,
-    equal_exprt(str[plus_exprt(qvar, offset)], prefix[qvar]));
+    equal_exprt(str[plus_exprt_with_overflow_check(qvar, offset)],
+                prefix[qvar]));
   axioms.push_back(a2);
 
   symbol_exprt witness=fresh_exist_index("witness_not_isprefix", index_type);
@@ -55,14 +56,13 @@ exprt string_constraint_generatort::add_axioms_for_is_prefix(
     axiom_for_is_positive_index(witness),
     and_exprt(
       prefix.axiom_for_is_strictly_longer_than(witness),
-      notequal_exprt(str[plus_exprt(witness, offset)], prefix[witness])));
+      notequal_exprt(str[plus_exprt_with_overflow_check(witness, offset)],
+                     prefix[witness])));
   or_exprt s0_notpref_s1(
     not_exprt(
-      str.axiom_for_is_longer_than(plus_exprt(prefix.length(), offset))),
-    and_exprt(
-      witness_diff,
       str.axiom_for_is_longer_than(
-        plus_exprt(prefix.length(), offset))));
+        plus_exprt_with_overflow_check(prefix.length(), offset))),
+    witness_diff);
 
   implies_exprt a3(not_exprt(isprefix), s0_notpref_s1);
   axioms.push_back(a3);
@@ -88,8 +88,8 @@ exprt string_constraint_generatort::add_axioms_for_is_prefix(
 {
   const function_application_exprt::argumentst &args=f.arguments();
   assert(f.type()==bool_typet() || f.type().id()==ID_c_bool);
-  string_exprt s0=add_axioms_for_string_expr(args[swap_arguments?1:0]);
-  string_exprt s1=add_axioms_for_string_expr(args[swap_arguments?0:1]);
+  string_exprt s0=get_string_expr(args[swap_arguments?1:0]);
+  string_exprt s1=get_string_expr(args[swap_arguments?0:1]);
   exprt offset;
   if(args.size()==2)
     offset=from_integer(0, s0.length().type());
@@ -121,7 +121,7 @@ exprt string_constraint_generatort::add_axioms_for_is_empty(
   // a2 : s0 => is_empty
 
   symbol_exprt is_empty=fresh_boolean("is_empty");
-  string_exprt s0=add_axioms_for_string_expr(args(f, 1)[0]);
+  string_exprt s0=get_string_expr(args(f, 1)[0]);
   axioms.push_back(implies_exprt(is_empty, s0.axiom_for_has_length(0)));
   axioms.push_back(implies_exprt(s0.axiom_for_has_length(0), is_empty));
   return typecast_exprt(is_empty, f.type());
@@ -150,8 +150,8 @@ exprt string_constraint_generatort::add_axioms_for_is_suffix(
 
   symbol_exprt issuffix=fresh_boolean("issuffix");
   typecast_exprt tc_issuffix(issuffix, f.type());
-  string_exprt s0=add_axioms_for_string_expr(args[swap_arguments?1:0]);
-  string_exprt s1=add_axioms_for_string_expr(args[swap_arguments?0:1]);
+  string_exprt s0=get_string_expr(args[swap_arguments?1:0]);
+  string_exprt s1=get_string_expr(args[swap_arguments?0:1]);
   const typet &index_type=s0.length().type();
 
   // We add axioms:
@@ -159,7 +159,7 @@ exprt string_constraint_generatort::add_axioms_for_is_suffix(
   // a2 : forall witness<s1.length.
   //     issufix => s1[witness]=s0[witness + s0.length-s1.length]
   // a3 : !issuffix =>
-  //   s1.length > s0.length
+  //   (s1.length > s0.length && witness=-1)
   //     || (s1.length > witness>=0
   //       &&s1[witness]!=s0[witness + s0.length-s1.length]
 
@@ -177,7 +177,8 @@ exprt string_constraint_generatort::add_axioms_for_is_suffix(
   exprt shifted=plus_exprt(
     witness, minus_exprt(s1.length(), s0.length()));
   or_exprt constr3(
-    s0.axiom_for_is_strictly_longer_than(s1),
+    and_exprt(s0.axiom_for_is_strictly_longer_than(s1),
+              equal_exprt(witness, from_integer(-1, index_type))),
     and_exprt(
       notequal_exprt(s0[witness], s1[shifted]),
       and_exprt(
@@ -207,9 +208,10 @@ exprt string_constraint_generatort::add_axioms_for_contains(
   assert(f.type()==bool_typet() || f.type().id()==ID_c_bool);
   symbol_exprt contains=fresh_boolean("contains");
   typecast_exprt tc_contains(contains, f.type());
-  string_exprt s0=add_axioms_for_string_expr(args(f, 2)[0]);
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[1]);
-  const typet &index_type=s0.type();
+  string_exprt s0=get_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[1]);
+  const refined_string_typet ref_type=to_refined_string_type(s0.type());
+  const typet &index_type=ref_type.get_index_type();
 
   // We add axioms:
   // a1 : contains => s0.length >= s1.length
diff --git a/src/solvers/refinement/string_constraint_generator_transformation.cpp b/src/solvers/refinement/string_constraint_generator_transformation.cpp
index 83735e0d5b5..f27fe5d4317 100644
--- a/src/solvers/refinement/string_constraint_generator_transformation.cpp
+++ b/src/solvers/refinement/string_constraint_generator_transformation.cpp
@@ -29,7 +29,7 @@ Function: string_constraint_generatort::add_axioms_for_set_length
 string_exprt string_constraint_generatort::add_axioms_for_set_length(
   const function_application_exprt &f)
 {
-  string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt s1=get_string_expr(args(f, 2)[0]);
   exprt k=args(f, 2)[1];
   const refined_string_typet &ref_type=to_refined_string_type(s1.type());
   string_exprt res=fresh_string(ref_type);
@@ -76,7 +76,7 @@ string_exprt string_constraint_generatort::add_axioms_for_substring(
 {
   const function_application_exprt::argumentst &args=f.arguments();
   assert(args.size()>=2);
-  string_exprt str=add_axioms_for_string_expr(args[0]);
+  string_exprt str=get_string_expr(args[0]);
   exprt i(args[1]);
   exprt j;
   if(args.size()==3)
@@ -110,7 +110,6 @@ string_exprt string_constraint_generatort::add_axioms_for_substring(
 {
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   const typet &index_type=ref_type.get_index_type();
-  symbol_exprt idx=fresh_exist_index("index_substring", index_type);
   assert(start.type()==index_type);
   assert(end.type()==index_type);
   string_exprt res=fresh_string(ref_type);
@@ -133,8 +132,11 @@ string_exprt string_constraint_generatort::add_axioms_for_substring(
   // Warning: check what to do if the string is not long enough
   axioms.push_back(str.axiom_for_is_longer_than(end));
 
-  string_constraintt a4(
-    idx, res.length(), equal_exprt(res[idx], str[plus_exprt(start, idx)]));
+  symbol_exprt idx=fresh_univ_index("QA_index_substring", index_type);
+  string_constraintt a4(idx,
+                        res.length(),
+                        equal_exprt(res[idx],
+                        str[plus_exprt_with_overflow_check(start, idx)]));
   axioms.push_back(a4);
   return res;
 }
@@ -154,7 +156,7 @@ Function: string_constraint_generatort::add_axioms_for_trim
 string_exprt string_constraint_generatort::add_axioms_for_trim(
   const function_application_exprt &expr)
 {
-  string_exprt str=add_axioms_for_string_expr(args(expr, 1)[0]);
+  string_exprt str=get_string_expr(args(expr, 1)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   const typet &index_type=ref_type.get_index_type();
   string_exprt res=fresh_string(ref_type);
@@ -173,7 +175,8 @@ string_exprt string_constraint_generatort::add_axioms_for_trim(
   // a8 : forall n<|s1|, s[idx+n]=s1[n]
   // a9 : (s[m]>' ' &&s[m+|s1|-1]>' ') || m=|s|
 
-  exprt a1=str.axiom_for_is_longer_than(plus_exprt(idx, res.length()));
+  exprt a1=str.axiom_for_is_longer_than(
+    plus_exprt_with_overflow_check(idx, res.length()));
   axioms.push_back(a1);
 
   binary_relation_exprt a2(idx, ID_ge, from_integer(0, index_type));
@@ -195,7 +198,8 @@ string_exprt string_constraint_generatort::add_axioms_for_trim(
   axioms.push_back(a6);
 
   symbol_exprt n2=fresh_univ_index("QA_index_trim2", index_type);
-  minus_exprt bound(str.length(), plus_exprt(idx, res.length()));
+  minus_exprt bound(str.length(), plus_exprt_with_overflow_check(idx,
+                                                                 res.length()));
   binary_relation_exprt eqn2(
     str[plus_exprt(idx, plus_exprt(res.length(), n2))],
     ID_le,
@@ -210,7 +214,8 @@ string_exprt string_constraint_generatort::add_axioms_for_trim(
   axioms.push_back(a8);
 
   minus_exprt index_before(
-    plus_exprt(idx, res.length()), from_integer(1, index_type));
+    plus_exprt_with_overflow_check(idx, res.length()),
+      from_integer(1, index_type));
   binary_relation_exprt no_space_before(str[index_before], ID_gt, space_char);
   or_exprt a9(
     equal_exprt(idx, str.length()),
@@ -236,7 +241,7 @@ Function: string_constraint_generatort::add_axioms_for_to_lower_case
 string_exprt string_constraint_generatort::add_axioms_for_to_lower_case(
   const function_application_exprt &expr)
 {
-  string_exprt str=add_axioms_for_string_expr(args(expr, 1)[0]);
+  string_exprt str=get_string_expr(args(expr, 1)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   const typet &char_type=ref_type.get_char_type();
   const typet &index_type=ref_type.get_index_type();
@@ -289,7 +294,7 @@ Function: string_constraint_generatort::add_axioms_for_to_upper_case
 string_exprt string_constraint_generatort::add_axioms_for_to_upper_case(
   const function_application_exprt &expr)
 {
-  string_exprt str=add_axioms_for_string_expr(args(expr, 1)[0]);
+  string_exprt str=get_string_expr(args(expr, 1)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   const typet &char_type=ref_type.get_char_type();
   const typet &index_type=ref_type.get_index_type();
@@ -345,7 +350,7 @@ Function: string_constraint_generatort::add_axioms_for_char_set
 string_exprt string_constraint_generatort::add_axioms_for_char_set(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt str=get_string_expr(args(f, 3)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   string_exprt res=fresh_string(ref_type);
   with_exprt sarrnew(str.content(), args(f, 3)[1], args(f, 3)[2]);
@@ -378,7 +383,7 @@ Function: string_constraint_generatort::add_axioms_for_replace
 string_exprt string_constraint_generatort::add_axioms_for_replace(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt str=get_string_expr(args(f, 3)[0]);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
   const exprt &old_char=args(f, 3)[1];
   const exprt &new_char=args(f, 3)[2];
@@ -421,10 +426,12 @@ Function: string_constraint_generatort::add_axioms_for_delete_char_at
 string_exprt string_constraint_generatort::add_axioms_for_delete_char_at(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 2)[0]);
+  string_exprt str=get_string_expr(args(f, 2)[0]);
   exprt index_one=from_integer(1, str.length().type());
   return add_axioms_for_delete(
-    str, args(f, 2)[1], plus_exprt(args(f, 2)[1], index_one));
+    str,
+    args(f, 2)[1],
+    plus_exprt_with_overflow_check(args(f, 2)[1], index_one));
 }
 
 /*******************************************************************\
@@ -468,6 +475,6 @@ Function: string_constraint_generatort::add_axioms_for_delete
 string_exprt string_constraint_generatort::add_axioms_for_delete(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 3)[0]);
+  string_exprt str=get_string_expr(args(f, 3)[0]);
   return add_axioms_for_delete(str, args(f, 3)[1], args(f, 3)[2]);
 }
diff --git a/src/solvers/refinement/string_constraint_generator_valueof.cpp b/src/solvers/refinement/string_constraint_generator_valueof.cpp
index d1030e5e085..10fe490259a 100644
--- a/src/solvers/refinement/string_constraint_generator_valueof.cpp
+++ b/src/solvers/refinement/string_constraint_generator_valueof.cpp
@@ -63,7 +63,8 @@ Function: string_constraint_generatort::add_axioms_from_float
 string_exprt string_constraint_generatort::add_axioms_from_float(
   const function_application_exprt &f)
 {
-  return add_axioms_from_float(args(f, 1)[0], false);
+  const refined_string_typet &ref_type=to_refined_string_type(f.type());
+  return add_axioms_from_float(args(f, 1)[0], ref_type, false);
 }
 
 /*******************************************************************\
@@ -81,7 +82,8 @@ Function: string_constraint_generatort::add_axioms_from_double
 string_exprt string_constraint_generatort::add_axioms_from_double(
   const function_application_exprt &f)
 {
-  return add_axioms_from_float(args(f, 1)[0], true);
+  const refined_string_typet &ref_type=to_refined_string_type(f.type());
+  return add_axioms_from_float(args(f, 1)[0], ref_type, true);
 }
 
 /*******************************************************************\
@@ -99,13 +101,12 @@ Function: string_constraint_generatort::add_axioms_from_float
 \*******************************************************************/
 
 string_exprt string_constraint_generatort::add_axioms_from_float(
-  const exprt &f, bool double_precision)
+  const exprt &f, const refined_string_typet &ref_type, bool double_precision)
 {
-  const refined_string_typet &ref_type=to_refined_string_type(f.type());
+  string_exprt res=fresh_string(ref_type);
   const typet &index_type=ref_type.get_index_type();
   const typet &char_type=ref_type.get_char_type();
-  string_exprt res=fresh_string(ref_type);
-  const exprt &index24=from_integer(24, ref_type.get_index_type());
+  const exprt &index24=from_integer(24, index_type);
   axioms.push_back(res.axiom_for_is_shorter_than(index24));
 
   string_exprt magnitude=fresh_string(ref_type);
@@ -323,13 +324,22 @@ string_exprt string_constraint_generatort::add_axioms_from_int(
   axioms.push_back(a1);
 
   exprt chr=res[0];
-  exprt starts_with_minus=equal_exprt(chr, minus_char);
-  exprt starts_with_digit=and_exprt(
+  equal_exprt starts_with_minus(chr, minus_char);
+  and_exprt starts_with_digit(
     binary_relation_exprt(chr, ID_ge, zero_char),
     binary_relation_exprt(chr, ID_le, nine_char));
   or_exprt a2(starts_with_digit, starts_with_minus);
   axioms.push_back(a2);
 
+  // These are constraints to detect number that requiere the maximum number
+  // of digits
+  exprt smallest_with_max_digits=
+    from_integer(smallest_by_digit(max_size-1), type);
+  binary_relation_exprt big_negative(
+    i, ID_le, unary_minus_exprt(smallest_with_max_digits));
+  binary_relation_exprt big_positive(i, ID_ge, smallest_with_max_digits);
+  or_exprt requieres_max_digits(big_negative, big_positive);
+
   for(size_t size=1; size<=max_size; size++)
   {
     // For each possible size, we add axioms:
@@ -387,13 +397,18 @@ string_exprt string_constraint_generatort::add_axioms_from_int(
       axioms.push_back(a6);
     }
 
-    // we have to be careful when exceeding the maximal size of integers
+    // when the size is close to the maximum, either the number is very big
+    // or it is negative
+    if(size==max_size-1)
+    {
+      implies_exprt a7(premise, or_exprt(requieres_max_digits,
+                                         starts_with_minus));
+      axioms.push_back(a7);
+    }
+    // when we reach the maximal size the number is very big in the negative
     if(size==max_size)
     {
-      exprt smallest_with_10_digits=from_integer(
-        smallest_by_digit(max_size), type);
-      binary_relation_exprt big(i, ID_ge, smallest_with_10_digits);
-      implies_exprt a7(premise, big);
+      implies_exprt a7(premise, and_exprt(starts_with_minus, big_negative));
       axioms.push_back(a7);
     }
   }
@@ -597,6 +612,60 @@ string_exprt string_constraint_generatort::add_axioms_for_value_of(
 
 /*******************************************************************\
 
+Function: string_constraint_generatort::add_axioms_for_correct_number_format
+
+  Inputs: function application with one string expression
+
+ Outputs: an boolean expression
+
+ Purpose: add axioms making the return value true if the given string is
+          a correct number
+
+\*******************************************************************/
+
+exprt string_constraint_generatort::add_axioms_for_correct_number_format(
+  const string_exprt &str, std::size_t max_size)
+{
+  symbol_exprt correct=fresh_boolean("correct_number_format");
+  const refined_string_typet &ref_type=to_refined_string_type(str.type());
+  const typet &char_type=ref_type.get_char_type();
+  const typet &index_type=ref_type.get_index_type();
+  exprt zero_char=constant_char('0', char_type);
+  exprt nine_char=constant_char('9', char_type);
+  exprt minus_char=constant_char('-', char_type);
+  exprt plus_char=constant_char('+', char_type);
+
+  exprt chr=str[0];
+  equal_exprt starts_with_minus(chr, minus_char);
+  equal_exprt starts_with_plus(chr, plus_char);
+  and_exprt starts_with_digit(
+    binary_relation_exprt(chr, ID_ge, zero_char),
+    binary_relation_exprt(chr, ID_le, nine_char));
+
+  or_exprt correct_first(
+    or_exprt(starts_with_minus, starts_with_plus), starts_with_digit);
+  exprt has_first=str.axiom_for_is_longer_than(from_integer(1, index_type));
+  implies_exprt a1(correct, and_exprt(has_first, correct_first));
+  axioms.push_back(a1);
+
+  exprt not_too_long=str.axiom_for_is_shorter_than(max_size);
+  axioms.push_back(not_too_long);
+
+  symbol_exprt qvar=fresh_univ_index("number_format", index_type);
+
+  and_exprt is_digit(
+    binary_relation_exprt(str[qvar], ID_ge, zero_char),
+    binary_relation_exprt(str[qvar], ID_le, nine_char));
+
+  string_constraintt a2(
+    qvar, from_integer(1, index_type), str.length(), correct, is_digit);
+
+  axioms.push_back(a2);
+  return correct;
+}
+
+/*******************************************************************\
+
 Function: string_constraint_generatort::add_axioms_for_parse_int
 
   Inputs: function application with one string expression
@@ -610,7 +679,7 @@ Function: string_constraint_generatort::add_axioms_for_parse_int
 exprt string_constraint_generatort::add_axioms_for_parse_int(
   const function_application_exprt &f)
 {
-  string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
+  string_exprt str=get_string_expr(args(f, 1)[0]);
   const typet &type=f.type();
   symbol_exprt i=fresh_symbol("parsed_int", type);
   const refined_string_typet &ref_type=to_refined_string_type(str.type());
@@ -626,6 +695,10 @@ exprt string_constraint_generatort::add_axioms_for_parse_int(
   exprt starts_with_plus=equal_exprt(chr, plus_char);
   exprt starts_with_digit=binary_relation_exprt(chr, ID_ge, zero_char);
 
+  // TODO: we should throw an exception when this does not hold:
+  exprt correct=add_axioms_for_correct_number_format(str);
+  axioms.push_back(correct);
+
   for(unsigned size=1; size<=10; size++)
   {
     exprt sum=from_integer(0, type);
diff --git a/src/solvers/refinement/string_refinement.cpp b/src/solvers/refinement/string_refinement.cpp
index 16b89bc43c8..164bb32c012 100644
--- a/src/solvers/refinement/string_refinement.cpp
+++ b/src/solvers/refinement/string_refinement.cpp
@@ -11,18 +11,40 @@ Author: Alberto Griggio, alberto.griggio@gmail.com
 \*******************************************************************/
 
 #include <sstream>
+#include <iomanip>
 #include <ansi-c/string_constant.h>
 #include <util/cprover_prefix.h>
 #include <util/replace_expr.h>
+#include <util/refined_string_type.h>
+#include <util/simplify_expr.h>
 #include <solvers/sat/satcheck.h>
 #include <solvers/refinement/string_refinement.h>
 #include <langapi/language_util.h>
+#include <java_bytecode/java_types.h>
+
+/*******************************************************************\
+
+Constructor: string_refinementt
+
+     Inputs: a namespace, a decision procedure, a bound on the number
+             of refinements and a boolean flag `concretize_result`
+
+    Purpose: refinement_bound is a bound on the number of refinement allowed.
+             if `concretize_result` is set to true, at the end of the decision
+             procedure, the solver try to find a concrete value for each
+             character
+
+\*******************************************************************/
 
 string_refinementt::string_refinementt(
-  const namespacet &_ns, propt &_prop, unsigned refinement_bound):
+  const namespacet &_ns,
+  propt &_prop,
+  unsigned refinement_bound):
   supert(_ns, _prop),
   use_counter_example(false),
-  initial_loop_bound(refinement_bound)
+  do_concretizing(false),
+  initial_loop_bound(refinement_bound),
+  non_empty_string(false)
 { }
 
 /*******************************************************************\
@@ -44,6 +66,52 @@ void string_refinementt::set_mode()
 
 /*******************************************************************\
 
+Function: string_refinementt::set_max_string_length
+
+  Inputs:
+    i - maximum length which is allowed for strings.
+        negative number means no limit
+
+ Purpose: Add constraints on the size of strings used in the
+          program.
+
+\*******************************************************************/
+
+void string_refinementt::set_max_string_length(int i)
+{
+  generator.max_string_length=i;
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::set_max_string_length
+
+ Purpose: Add constraints on the size of nondet character arrays
+          to ensure they have length at least 1
+
+\*******************************************************************/
+
+void string_refinementt::enforce_non_empty_string()
+{
+  non_empty_string=true;
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::enforce_printable_characters
+
+ Purpose: Add constraints on characters used in the program
+          to ensure they are printable
+
+\*******************************************************************/
+
+void string_refinementt::enforce_printable_characters()
+{
+  generator.force_printable_characters=true;
+}
+
+/*******************************************************************\
+
 Function: string_refinementt::display_index_set
 
  Purpose: display the current index set, for debugging
@@ -52,15 +120,27 @@ Function: string_refinementt::display_index_set
 
 void string_refinementt::display_index_set()
 {
+  std::size_t count=0;
+  std::size_t count_current=0;
   for(const auto &i : index_set)
   {
     const exprt &s=i.first;
-    debug() << "IS(" << from_expr(s) << ")=={";
+    debug() << "IS(" << from_expr(s) << ")=={" << eom;
 
     for(auto j : i.second)
-      debug() << from_expr(j) << "; ";
+    {
+      if(current_index_set[i.first].find(j)!=current_index_set[i.first].end())
+      {
+        count_current++;
+        debug() << "**";
+      }
+      debug() << "  " << from_expr(j) << ";" << eom;
+      count++;
+    }
     debug() << "}"  << eom;
   }
+  debug() << count << " elements in index set (" << count_current
+          << " newly added)" << eom;
 }
 
 /*******************************************************************\
@@ -100,152 +180,350 @@ void string_refinementt::add_instantiations()
 
 /*******************************************************************\
 
-Function: string_refinementt::convert_rest
-
-  Inputs: an expression
+Function: string_refinementt::add_symbol_to_symbol_map()
 
- Outputs: a literal
+  Inputs: a symbol and the expression to map it to
 
- Purpose: if the expression is a function application, we convert it
-          using our own convert_function_application method
+ Purpose: keeps a map of symbols to expressions, such as none of the
+          mapped values exist as a key
 
 \*******************************************************************/
 
-literalt string_refinementt::convert_rest(const exprt &expr)
+void string_refinementt::add_symbol_to_symbol_map
+(const exprt &lhs, const exprt &rhs)
 {
-  if(expr.id()==ID_function_application)
+  assert(lhs.id()==ID_symbol);
+
+  // We insert the mapped value of the rhs, if it exists.
+  auto it=symbol_resolve.find(rhs);
+  const exprt &new_rhs=it!=symbol_resolve.end()?it->second:rhs;
+
+  symbol_resolve[lhs]=new_rhs;
+  reverse_symbol_resolve[new_rhs].push_back(lhs);
+
+  std::list<exprt> symbols_to_update_with_new_rhs(reverse_symbol_resolve[rhs]);
+  for(exprt item : symbols_to_update_with_new_rhs)
   {
-    // can occur in __CPROVER_assume
-    bvt bv=convert_function_application(to_function_application_expr(expr));
-    assert(bv.size()==1);
-    return bv[0];
+    symbol_resolve[item]=new_rhs;
+    reverse_symbol_resolve[new_rhs].push_back(item);
   }
-  else
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::set_char_array_equality()
+
+  Inputs: the rhs and lhs of an equality over character arrays
+
+ Purpose: add axioms if the rhs is a character array
+
+\*******************************************************************/
+
+void string_refinementt::set_char_array_equality(
+  const exprt &lhs, const exprt &rhs)
+{
+  assert(lhs.id()==ID_symbol);
+
+  if(rhs.id()==ID_array && rhs.type().id()==ID_array)
   {
-    return supert::convert_rest(expr);
+    const typet &index_type=to_array_type(rhs.type()).size().type();
+    for(size_t i=0, ilim=rhs.operands().size(); i!=ilim; ++i)
+    {
+      // Introduce axioms to map symbolic rhs to its char array.
+      index_exprt arraycell(rhs, from_integer(i, index_type));
+      equal_exprt arrayeq(arraycell, rhs.operands()[i]);
+      add_lemma(arrayeq, false);
+#if 0
+      generator.axioms.push_back(arrayeq);
+#endif
+    }
   }
+  // At least for Java (as it is currently pre-processed), we need not consider
+  // other cases, because all character arrays find themselves on the rhs of an
+  // equality. Note that this might not be the case for other languages.
 }
 
 /*******************************************************************\
 
-Function: string_refinementt::convert_symbol
+Function: string_refinementt::substitute_function_applications()
 
-  Inputs: an expression
+  Inputs: an expression containing function applications
 
- Outputs: a bitvector
+ Outputs: an epression containing no function application
 
- Purpose: if the expression as string type, look up for the string in the
-          list of string symbols that we maintain, and convert it;
-          otherwise use the method of the parent class
+ Purpose: remove functions applications and create the necessary
+          axioms
 
 \*******************************************************************/
 
-bvt string_refinementt::convert_symbol(const exprt &expr)
+exprt string_refinementt::substitute_function_applications(exprt expr)
 {
-  const typet &type=expr.type();
-  const irep_idt &identifier=expr.get(ID_identifier);
-  assert(!identifier.empty());
+  for(size_t i=0; i<expr.operands().size(); ++i)
+  {
+    // TODO: only copy when necessary
+    exprt op(expr.operands()[i]);
+    expr.operands()[i]=substitute_function_applications(op);
+  }
 
-  if(refined_string_typet::is_unrefined_string_type(type))
+  if(expr.id()==ID_function_application)
   {
-    string_exprt str=
-      generator.find_or_add_string_of_symbol(to_symbol_expr(expr));
-    bvt bv=convert_bv(str);
-    return bv;
+    function_application_exprt f=to_function_application_expr(expr);
+    return generator.add_axioms_for_function_application(f);
   }
-  else
-    return supert::convert_symbol(expr);
+
+  return expr;
+}
+
+bool string_refinementt::is_char_array(const typet &type) const
+{
+  if(type.id()==ID_symbol)
+    return is_char_array(ns.follow(type));
+
+  return (type.id()==ID_array && type.subtype()==java_char_type());
 }
 
 /*******************************************************************\
 
-Function: string_refinementt::convert_function_application
+Function: string_refinementt::boolbv_set_equality_to_true
 
-  Inputs: a function_application
+  Inputs: the lhs and rhs of an equality expression
 
- Outputs: a bitvector
+ Outputs: false if the lemmas were added successfully, true otherwise
 
- Purpose: generate an expression, add lemmas stating that this expression
-          corresponds to the result of the given function call, and convert
-          this expression
+ Purpose: add lemmas to the solver corresponding to the given equation
 
 \*******************************************************************/
 
-bvt string_refinementt::convert_function_application
-(const function_application_exprt &expr)
+bool string_refinementt::add_axioms_for_string_assigns(const exprt &lhs,
+                                                       const exprt &rhs)
 {
-  debug() << "string_refinementt::convert_function_application "
-          << from_expr(expr) << eom;
-  exprt f=generator.add_axioms_for_function_application(expr);
-  return convert_bv(f);
+  if(is_char_array(rhs.type()))
+  {
+    set_char_array_equality(lhs, rhs);
+    if(rhs.id() == ID_symbol || rhs.id() == ID_array)
+    {
+      add_symbol_to_symbol_map(lhs, rhs);
+      return false;
+    }
+    else if(rhs.id() == ID_nondet_symbol)
+    {
+      add_symbol_to_symbol_map(
+        lhs, generator.fresh_symbol("nondet_array", lhs.type()));
+      return false;
+    }
+    else
+    {
+      debug() << "string_refinement warning: not handling char_array: "
+              << from_expr(rhs) << eom;
+      return true;
+    }
+  }
+  if(refined_string_typet::is_refined_string_type(rhs.type()))
+  {
+    exprt refined_rhs=generator.add_axioms_for_refined_string(rhs);
+    add_symbol_to_symbol_map(lhs, refined_rhs);
+    return false;
+  }
+  // Other cases are to be handled by supert::set_to.
+  return true;
 }
 
 /*******************************************************************\
 
-Function: string_refinementt::boolbv_set_equality_to_true
+Function: string_refinementt::concretize_string
 
-  Inputs: an equality expression
+  Input:
+    expr - an expression
 
- Outputs: a Boolean flag to signal a proble
+ Purpose: If the expression is of type string, then adds constants
+          to the index set to force the solver to pick concrete values
+          for each character, and fill the map `found_length`
 
- Purpose: add lemmas to the solver corresponding to the given equation
+\*******************************************************************/
+
+void string_refinementt::concretize_string(const exprt &expr)
+{
+  if(refined_string_typet::is_refined_string_type(expr.type()))
+  {
+    string_exprt str=to_string_expr(expr);
+    exprt length=get(str.length());
+    add_lemma(equal_exprt(str.length(), length));
+    exprt content=str.content();
+    replace_expr(symbol_resolve, content);
+    found_length[content]=length;
+    mp_integer found_length;
+    if(!to_integer(length, found_length))
+    {
+      assert(found_length.is_long());
+      if(found_length < 0)
+      {
+        debug() << "concretize_results: WARNING found length is negative"
+                << eom;
+      }
+      else
+      {
+        size_t concretize_limit=found_length.to_long();
+        concretize_limit=concretize_limit>MAX_CONCRETE_STRING_SIZE?
+              MAX_CONCRETE_STRING_SIZE:concretize_limit;
+        exprt content_expr=str.content();
+        for(size_t i=0; i<concretize_limit; ++i)
+        {
+          auto i_expr=from_integer(i, str.length().type());
+          debug() << "Concretizing " << from_expr(content_expr)
+                  << " / " << i << eom;
+          current_index_set[str.content()].insert(i_expr);
+          index_set[str.content()].insert(i_expr);
+        }
+      }
+    }
+  }
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::concretize_results
+
+ Purpose: For each string whose length has been solved, add constants
+          to the index set to force the solver to pick concrete values
+          for each character, and fill the map `found_length`
 
 \*******************************************************************/
 
-bool string_refinementt::boolbv_set_equality_to_true(const equal_exprt &expr)
+void string_refinementt::concretize_results()
 {
-  if(!equality_propagation)
-    return true;
+  for(const auto& it : symbol_resolve)
+    concretize_string(it.second);
+  for(const auto& it : generator.created_strings)
+    concretize_string(it);
+  add_instantiations();
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::concretize_lengths
+
+ Purpose: For each string whose length has been solved, add constants
+          to the map `found_length`
+
+\*******************************************************************/
+
+void string_refinementt::concretize_lengths()
+{
+  for(const auto& it : symbol_resolve)
+  {
+    if(refined_string_typet::is_refined_string_type(it.second.type()))
+    {
+      string_exprt str=to_string_expr(it.second);
+      exprt length=get(str.length());
+      exprt content=str.content();
+      replace_expr(symbol_resolve, content);
+      found_length[content]=length;
+     }
+  }
+  for(const auto& it : generator.created_strings)
+  {
+    if(refined_string_typet::is_refined_string_type(it.type()))
+    {
+      string_exprt str=to_string_expr(it);
+      exprt length=get(str.length());
+      exprt content=str.content();
+      replace_expr(symbol_resolve, content);
+      found_length[content]=length;
+     }
+  }
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::set_to
+
+  Inputs: an expression and the value to set it to
+
+ Purpose: add lemmas representing the setting of an expression to a
+          given value
 
-  // We should not do that everytime, but I cannot find
-  // another good entry point
+\*******************************************************************/
+
+void string_refinementt::set_to(const exprt &expr, bool value)
+{
+  assert(equality_propagation);
+
+  // TODO: remove the mode field of generator since we should be language
+  // independent.
+  // We only set the mode once.
   if(generator.get_mode()==ID_unknown)
     set_mode();
 
-  typet type=ns.follow(expr.lhs().type());
-
-  if(expr.lhs().id()==ID_symbol &&
-     // We can have affectation of string from StringBuilder or CharSequence
-     // type==ns.follow(expr.rhs().type()) &&
-     type.id()!=ID_bool)
+  if(expr.id()==ID_equal)
   {
-    debug() << "string_refinementt " << from_expr(expr.lhs()) << " <- "
-            << from_expr(expr.rhs()) << eom;
+    equal_exprt eq_expr=to_equal_expr(expr);
+
+    if(eq_expr.lhs().type()!=eq_expr.rhs().type())
+    {
+      debug() << "(sr::set_to) WARNING: ignoring "
+              << from_expr(expr) << " [inconsistent types]" << eom;
+      return;
+    }
+
+    if(expr.type().id()!=ID_bool)
+    {
+      error() << "string_refinementt::set_to got non-boolean operand: "
+              << expr.pretty() << eom;
+      throw 0;
+    }
 
+    // Preprocessing to remove function applications.
+    const exprt &lhs=eq_expr.lhs();
+    debug() << "(sr::set_to) " << from_expr(lhs)
+            << " = " << from_expr(eq_expr.rhs()) << eom;
 
-    if(expr.rhs().id()==ID_typecast)
+    // TODO: See if this happens at all.
+    if(lhs.id()!=ID_symbol)
     {
-      exprt uncast=to_typecast_expr(expr.rhs()).op();
-      if(refined_string_typet::is_unrefined_string_type(uncast.type()))
+      debug() << "(sr::set_to) WARNING: ignoring "
+              << from_expr(expr) << eom;
+      return;
+    }
+
+    exprt subst_rhs=substitute_function_applications(eq_expr.rhs());
+    if(eq_expr.lhs().type()!=subst_rhs.type())
+    {
+      if(eq_expr.lhs().type().id() != ID_array ||
+         subst_rhs.type().id() != ID_array ||
+         eq_expr.lhs().type().subtype() != subst_rhs.type().subtype())
+      {
+        debug() << "(sr::set_to) WARNING: ignoring "
+                << from_expr(expr) << " [inconsistent types after substitution]"
+                << eom;
+        return;
+      }
+      else
       {
-        debug() << "(sr) detected casted string" << eom;
-        symbol_exprt sym=to_symbol_expr(expr.lhs());
-        generator.set_string_symbol_equal_to_expr(sym, uncast);
-        return false;
+        debug() << "(sr::set_to) accepting arrays with "
+                << "same subtype but different sizes" << eom;
       }
     }
 
-    if(refined_string_typet::is_unrefined_string_type(type))
+    if(value)
     {
-      symbol_exprt sym=to_symbol_expr(expr.lhs());
-      generator.set_string_symbol_equal_to_expr(sym, expr.rhs());
-      return false;
+      if(!add_axioms_for_string_assigns(lhs, subst_rhs))
+        return;
     }
-    else if(type==ns.follow(expr.rhs().type()))
+    else
     {
-      if(is_unbounded_array(type))
-        return true;
-      bvt bv1=convert_bv(expr.rhs());
-      const irep_idt &identifier=
-        to_symbol_expr(expr.lhs()).get_identifier();
-      map.set_literals(identifier, type, bv1);
-      if(freeze_all)
-        set_frozen(bv1);
-      return false;
+      // TODO: Something should also be done if value is false.
+      assert(!is_char_array(eq_expr.rhs().type()));
+      assert(!refined_string_typet::is_refined_string_type(
+        eq_expr.rhs().type()));
     }
-  }
 
-  return true;
+    non_string_axioms.push_back(std::make_pair(equal_exprt(lhs, subst_rhs),
+                                               value));
+  }
+  // We keep a list of the axioms to give to supert::set_to in order to
+  // substitute the symbols in dec_solve().
+  else
+    non_string_axioms.push_back(std::make_pair(expr, value));
 }
 
 /*******************************************************************\
@@ -261,7 +539,18 @@ Function: string_refinementt::dec_solve
 
 decision_proceduret::resultt string_refinementt::dec_solve()
 {
-  for(const exprt &axiom : generator.axioms)
+  // Substitute all symbols to char arrays in the axioms to give to
+  // supert::set_to().
+  for(std::pair<exprt, bool> &pair : non_string_axioms)
+  {
+    replace_expr(symbol_resolve, pair.first);
+    debug() << "super::set_to " << from_expr(pair.first) << eom;
+    supert::set_to(pair.first, pair.second);
+  }
+
+  for(exprt &axiom : generator.axioms)
+  {
+    replace_expr(symbol_resolve, axiom);
     if(axiom.id()==ID_string_constraint)
     {
       string_constraintt c=to_string_constraint(axiom);
@@ -282,6 +571,7 @@ decision_proceduret::resultt string_refinementt::dec_solve()
     {
       add_lemma(axiom);
     }
+  }
 
   initial_index_set(universal_axioms);
   update_index_set(cur);
@@ -302,6 +592,7 @@ decision_proceduret::resultt string_refinementt::dec_solve()
       else
       {
         debug() << "check_SAT: the model is correct" << eom;
+        concretize_lengths();
         return D_SATISFIABLE;
       }
 
@@ -318,7 +609,13 @@ decision_proceduret::resultt string_refinementt::dec_solve()
       if(current_index_set.empty())
       {
         debug() << "current index set is empty" << eom;
-        return D_SATISFIABLE;
+        if(do_concretizing)
+        {
+          concretize_results();
+          do_concretizing=false;
+        }
+        else
+          return D_SATISFIABLE;
       }
 
       display_index_set();
@@ -367,178 +664,459 @@ bvt string_refinementt::convert_bool_bv(const exprt &boole, const exprt &orig)
 
 Function: string_refinementt::add_lemma
 
-  Inputs: a lemma
+  Inputs: a lemma and Boolean value stating whether the lemma should
+          be added to the index set.
 
  Purpose: add the given lemma to the solver
 
 \*******************************************************************/
 
-void string_refinementt::add_lemma(const exprt &lemma, bool add_to_index_set)
+void string_refinementt::add_lemma(
+  const exprt &lemma, bool _simplify, bool add_to_index_set)
 {
   if(!seen_instances.insert(lemma).second)
     return;
 
-  if(lemma.is_true())
+  if(add_to_index_set)
+    cur.push_back(lemma);
+
+  exprt simple_lemma=lemma;
+  if(_simplify)
+    simplify(simple_lemma, ns);
+
+  if(simple_lemma.is_true())
   {
+#if 0
     debug() << "string_refinementt::add_lemma : tautology" << eom;
+#endif
     return;
   }
 
-  debug() << "adding lemma " << from_expr(lemma) << eom;
+  debug() << "adding lemma " << from_expr(simple_lemma) << eom;
 
-  prop.l_set_to_true(convert(lemma));
-  if(add_to_index_set)
-    cur.push_back(lemma);
+  prop.l_set_to_true(convert(simple_lemma));
 }
 
 /*******************************************************************\
 
-Function: string_refinementt::string_of_array
+Function: string_refinementt::get_array
 
-  Inputs: a constant array expression and a integer expression
+  Inputs: an expression representing an array and an expression
+          representing an integer
 
- Outputs: a string
+ Outputs: an array expression or an array_of_exprt
 
- Purpose: convert the content of a string to a more readable representation.
-          This should only be used for debbuging.
+ Purpose: get a model of an array and put it in a certain form.
+          If the size cannot be obtained or if it is too big, return an
+          empty array.
 
 \*******************************************************************/
 
-std::string string_refinementt::string_of_array(
-  const exprt &arr, const exprt &size) const
+exprt string_refinementt::get_array(const exprt &arr, const exprt &size) const
 {
-  if(size.id()!=ID_constant)
-    return "string of unknown size";
+  exprt arr_val=get_array(arr);
+  exprt size_val=supert::get(size);
+  size_val=simplify_expr(size_val, ns);
+  typet char_type=arr.type().subtype();
+  typet index_type=size.type();
+  array_typet empty_ret_type(char_type, from_integer(0, index_type));
+  array_of_exprt empty_ret(from_integer(0, char_type), empty_ret_type);
+
+  if(size_val.id()!=ID_constant)
+  {
+#if 0
+    debug() << "(sr::get_array) string of unknown size: "
+            << from_expr(size_val) << eom;
+#endif
+    return empty_ret;
+  }
+
   unsigned n;
-  if(to_unsigned_integer(to_constant_expr(size), n))
-    n=0;
+  if(to_unsigned_integer(to_constant_expr(size_val), n))
+  {
+#if 0
+    debug() << "(sr::get_array) size is not valid" << eom;
+#endif
+    return empty_ret;
+  }
+
+  array_typet ret_type(char_type, from_integer(n, index_type));
+  array_exprt ret(ret_type);
 
   if(n>MAX_CONCRETE_STRING_SIZE)
-    return "very long string";
+  {
+#if 0
+    debug() << "(sr::get_array) long string (size=" << n << ")" << eom;
+#endif
+    return empty_ret;
+  }
+
   if(n==0)
-    return "\"\"";
+  {
+#if 0
+    debug() << "(sr::get_array) empty string" << eom;
+#endif
+    return empty_ret;
+  }
 
-  std::ostringstream buf;
-  buf << "\"";
-  exprt val=get(arr);
+  std::vector<unsigned> concrete_array(n);
 
-  if(val.id()=="array-list")
+  if(arr_val.id()=="array-list")
   {
-    for(size_t i=0; i<val.operands().size()/2; i++)
+    for(size_t i=0; i<arr_val.operands().size()/2; i++)
     {
-      exprt index=val.operands()[i*2];
+      exprt index=arr_val.operands()[i*2];
       unsigned idx;
       if(!to_unsigned_integer(to_constant_expr(index), idx))
       {
         if(idx<n)
         {
-          exprt value=val.operands()[i*2+1];
-          unsigned c;
-          if(!to_unsigned_integer(to_constant_expr(value), c))
-            buf << static_cast<char>(c);
+          exprt value=arr_val.operands()[i*2+1];
+          to_unsigned_integer(to_constant_expr(value), concrete_array[idx]);
         }
       }
     }
   }
+  else if(arr_val.id()==ID_array)
+  {
+    for(size_t i=0; i<arr_val.operands().size() && i<n; i++)
+    {
+      unsigned c;
+      exprt op=arr_val.operands()[i];
+      if(op.id()==ID_constant)
+      {
+        to_unsigned_integer(to_constant_expr(op), c);
+        concrete_array[i]=c;
+      }
+    }
+  }
   else
   {
-    return "unable to get array-list";
+#if 0
+    debug() << "unable to get array-list value of " << from_expr(arr)
+            << " of size " << n << eom;
+#endif
+    return array_of_exprt(from_integer(0, char_type), ret_type);
   }
 
-  buf << "\"";
-  return buf.str();
+  for(size_t i=0; i<n; i++)
+  {
+    exprt c_expr=from_integer(concrete_array[i], char_type);
+    ret.move_to_operands(c_expr);
+  }
+
+  return ret;
 }
 
+
 /*******************************************************************\
 
 Function: string_refinementt::get_array
 
-  Inputs: an array expression and a integer expression
+  Inputs: an expression representing an array
 
- Outputs: a string expression
+ Outputs: an expression
 
- Purpose: gets a model of an array and put it in a certain form
+ Purpose: get a model of an array of unknown size and infer the size if
+          possible
 
 \*******************************************************************/
 
-exprt string_refinementt::get_array(const exprt &arr, const exprt &size)
+exprt string_refinementt::get_array(const exprt &arr) const
 {
-  exprt val=get(arr);
-  typet char_type=arr.type().subtype();
-  typet index_type=size.type();
+  exprt arr_model=supert::get(arr);
+  if(arr_model.id()==ID_array)
+  {
+    array_typet &arr_type=to_array_type(arr_model.type());
+    arr_type.size()=from_integer(
+      arr_model.operands().size(), arr_type.size().type());
+  }
+  return arr_model;
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::string_of_array
+
+  Inputs: a constant array expression and a integer expression
+
+ Outputs: a string
 
-  if(val.id()=="array-list")
+ Purpose: convert the content of a string to a more readable representation.
+          This should only be used for debbuging.
+
+\*******************************************************************/
+
+std::string string_refinementt::string_of_array(const array_exprt &arr)
+{
+  unsigned n;
+  if(arr.type().id()!=ID_array)
+      return std::string("");
+
+  exprt size_expr=to_array_type(arr.type()).size();
+  assert(size_expr.id()==ID_constant);
+  to_unsigned_integer(to_constant_expr(size_expr), n);
+  std::string str(n, '?');
+
+  std::ostringstream result;
+  std::locale loc;
+
+  for(size_t i=0; i<arr.operands().size() && i<n; i++)
   {
-    array_typet ret_type(char_type, infinity_exprt(index_type));
-    exprt ret=array_of_exprt(from_integer(0, char_type), ret_type);
+    // TODO: factorize with utf16_little_endian_to_ascii
+    unsigned c;
+    exprt arr_i=arr.operands()[i];
+    assert(arr_i.id()==ID_constant);
+    to_unsigned_integer(to_constant_expr(arr_i), c);
+    if(c<=255 && c>=32)
+      result << (unsigned char) c;
+    else
+    {
+      result << "\\u" << std::hex << std::setw(4) << std::setfill('0')
+             << (unsigned int) c;
+    }
+  }
+
+  return result.str();
+}
+
+/*******************************************************************\
 
-    for(size_t i=0; i<val.operands().size()/2; i++)
+Function: string_refinementt::fill_model
+
+ Purpose: Fill in `current_model` by mapping the variables created by
+          the solver to constant expressions given by the current model
+
+\*******************************************************************/
+
+void string_refinementt::fill_model()
+{
+  for(auto it : symbol_resolve)
+  {
+    if(refined_string_typet::is_refined_string_type(it.second.type()))
     {
-      exprt index=val.operands()[i*2];
-      assert(index.type()==index_type);
-      exprt value=val.operands()[i*2+1];
-      assert(value.type()==char_type);
-      ret=with_exprt(ret, index, value);
+      string_exprt refined=to_string_expr(it.second);
+      // TODO: check whith this is necessary:
+      replace_expr(symbol_resolve, refined);
+      const exprt &econtent=refined.content();
+      const exprt &elength=refined.length();
+
+      exprt len=supert::get(elength);
+      len=simplify_expr(len, ns);
+      exprt arr=get_array(econtent, len);
+
+      current_model[elength]=len;
+      current_model[econtent]=arr;
+      debug() << from_expr(to_symbol_expr(it.first)) << "="
+              << from_expr(refined);
+
+      if(arr.id()==ID_array)
+        debug() << " = \"" << string_of_array(to_array_expr(arr))
+                << "\" (size:" << from_expr(len) << ")"<< eom;
+      else
+        debug() << " = " << from_expr(arr) << " (size:" << from_expr(len)
+                << ")" << eom;
+    }
+    else
+    {
+      assert(is_char_array(it.second.type()));
+      exprt arr=it.second;
+      replace_expr(symbol_resolve, arr);
+      replace_expr(current_model, arr);
+      exprt arr_model=get_array(arr);
+      current_model[it.first]=arr_model;
+
+      debug() << from_expr(to_symbol_expr(it.first)) << "="
+              << from_expr(arr) << " = " << from_expr(arr_model) << "" << eom;
     }
-    return ret;
+  }
+
+  for(auto it : generator.boolean_symbols)
+  {
+      debug() << "" << it.get_identifier() << " := "
+              << from_expr(supert::get(it)) << eom;
+      current_model[it]=supert::get(it);
+  }
+
+  for(auto it : generator.index_symbols)
+  {
+     debug() << "" << it.get_identifier() << " := "
+              << from_expr(supert::get(it)) << eom;
+     current_model[it]=supert::get(it);
+  }
+}
+
+
+/*******************************************************************\
+
+Function: string_refinementt::substitute_array_with_expr()
+
+  Inputs:
+    expr - A (possibly nested) 'with' expression on an `array_of`
+           expression
+    index - An index with which to build the equality condition
+
+ Outputs: An expression containing no 'with' expression
+
+ Purpose: Create a new expression where 'with' expressions on arrays
+          are replaced by 'if' expressions.
+          e.g. for an array access arr[x], where:
+               `arr := array_of(12) with {0:=24} with {2:=42}`
+               the constructed expression will be:
+               `index==0 ? 24 : index==2 ? 42 : 12`
+
+\*******************************************************************/
+
+exprt string_refinementt::substitute_array_with_expr
+  (exprt &expr, exprt &index) const
+{
+  if(expr.id()==ID_with)
+  {
+    with_exprt &with_expr=to_with_expr(expr);
+    return if_exprt(equal_exprt(index, with_expr.where()),
+                    with_expr.new_value(),
+                    substitute_array_with_expr(with_expr.old(), index));
   }
   else
   {
-    debug() << "unable to get array-list value of "
-            << from_expr(val) << eom;
-    return arr;
+    // Only handle 'with' expressions on 'array_of' expressions.
+    assert(expr.id()==ID_array_of);
+    return to_array_of_expr(expr).what();
   }
 }
 
 /*******************************************************************\
 
-Function: string_refinementt::check_axioms
+Function: string_refinementt::substitute_array_access()
 
- Outputs: a Boolean
+  Inputs:
+    expr - an expression containing array accesses
 
- Purpose: return true if the current model satisfies all the axioms
+ Outputs: an expression containing no array access
+
+ Purpose: create an equivalent expression where array accesses and
+          'with' expressions are replaced by 'if' expressions.
+          e.g. for an array access arr[x], where:
+               `arr := {12, 24, 48}`
+               the constructed expression will be:
+               `index==0 ? 12 : index==1 ? 24 : 48`
 
 \*******************************************************************/
 
-bool string_refinementt::check_axioms()
+exprt string_refinementt::substitute_array_access(exprt &expr) const
 {
-  debug() << "string_refinementt::check_axioms: ==============="
-          << "===========================================" << eom;
-  debug() << "string_refinementt::check_axioms: build the"
-          << " interpretation from the model of the prop_solver" << eom;
-  replace_mapt fmodel;
+  for(size_t i=0; i<expr.operands().size(); ++i)
+  {
+    // TODO: only copy when necessary
+    exprt op(expr.operands()[i]);
+    expr.operands()[i]=substitute_array_access(op);
+  }
 
-  for(auto it : generator.symbol_to_string)
+  if(expr.id()==ID_index)
   {
-    string_exprt refined=it.second;
-    const exprt &econtent=refined.content();
-    const exprt &elength=refined.length();
-
-    exprt len=get(elength);
-    exprt arr=get_array(econtent, len);
-
-    fmodel[elength]=len;
-    fmodel[econtent]=arr;
-    debug() << it.first << "=" << from_expr(it.second)
-            << " of length " << from_expr(len) <<" := " << eom
-            << from_expr(get(econtent)) << eom
-            << string_of_array(econtent, len) << eom;
+    index_exprt &index_expr=to_index_expr(expr);
+
+    if(index_expr.array().id()==ID_symbol)
+    {
+      return index_expr;
+    }
+
+    if(index_expr.array().id()==ID_with)
+    {
+      exprt subst=substitute_array_with_expr(index_expr.array(),
+                                             index_expr.index());
+      return subst;
+    }
+
+    if(index_expr.array().id()==ID_array_of)
+    {
+      return to_array_of_expr(index_expr.array()).op();
+    }
+
+    assert(index_expr.array().id()==ID_array);
+    array_exprt &array_expr=to_array_expr(index_expr.array());
+
+    size_t last_index=array_expr.operands().size()-1;
+    assert(last_index>=0);
+    exprt ite=array_expr.operands()[last_index];
+
+    for(long i=last_index-1; i>=0; --i)
+    {
+      equal_exprt equals(index_expr.index(), from_integer(i, java_int_type()));
+      ite=if_exprt(equals,
+                   array_expr.operands()[i],
+                   ite);
+    }
+    return ite;
   }
+  return expr;
+}
 
-  for(auto it : generator.boolean_symbols)
+/*******************************************************************\
+
+Function: string_refinementt::add_negation_of_constraint_to_solver
+
+  Inputs: a string constraint and a solver for non string expressions
+
+ Purpose: negates the constraint and add it to the solver.
+          the intended usage is to find an assignement of the universal
+          variable that would violate the axiom,
+          to avoid false positives the symbols other than the universal
+          variable should have been replaced by there valuation in the
+          current model
+
+\*******************************************************************/
+
+void string_refinementt::add_negation_of_constraint_to_solver(
+  const string_constraintt &axiom, supert &solver)
+{
+  exprt lb=axiom.lower_bound();
+  exprt ub=axiom.upper_bound();
+  if(lb.id()==ID_constant && ub.id()==ID_constant)
   {
-    debug() << "" << it.get_identifier() << " := "
-            << from_expr(get(it)) << eom;
-    fmodel[it]=get(it);
+    mp_integer lb_int, ub_int;
+    to_integer(to_constant_expr(lb), lb_int);
+    to_integer(to_constant_expr(ub), ub_int);
+    if(ub_int<=lb_int)
+    {
+      debug() << "empty constraint with current model" << eom;
+      solver << false_exprt();
+      return;
+    }
   }
 
-  for(auto it : generator.index_symbols)
+  if(axiom.premise()==false_exprt())
   {
-    debug() << "" << it.get_identifier() << " := "
-            << from_expr(get(it)) << eom;
-    fmodel[it]=get(it);
+      debug() << "(string_refinement::check_axioms) adding false" << eom;
+      solver << false_exprt();
+      return;
   }
 
+  and_exprt premise(axiom.premise(), axiom.univ_within_bounds());
+  and_exprt negaxiom(premise, not_exprt(axiom.body()));
+
+  debug() << "(sr::check_axioms) negated axiom: " << from_expr(negaxiom) << eom;
+  solver << substitute_array_access(negaxiom);
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::check_axioms
+
+ Outputs: a Boolean
+
+ Purpose: return true if the current model satisfies all the axioms
+
+\*******************************************************************/
+
+bool string_refinementt::check_axioms()
+{
+  debug() << "string_refinementt::check_axioms: ==============="
+          << "===========================================" << eom;
+  debug() << "string_refinementt::check_axioms: build the"
+          << " interpretation from the model of the prop_solver" << eom;
+  fill_model();
+
   // Maps from indexes of violated universal axiom to a witness of violation
   std::map<size_t, exprt> violated;
 
@@ -547,21 +1125,28 @@ bool string_refinementt::check_axioms()
   for(size_t i=0; i<universal_axioms.size(); i++)
   {
     const string_constraintt &axiom=universal_axioms[i];
+    symbol_exprt univ_var=axiom.univ_var();
+    exprt bound_inf=axiom.lower_bound();
+    exprt bound_sup=axiom.upper_bound();
+    exprt prem=axiom.premise();
+    exprt body=axiom.body();
 
-    exprt negaxiom=and_exprt(axiom.premise(), not_exprt(axiom.body()));
-    replace_expr(fmodel, negaxiom);
-
-    debug() << "negaxiom: " << from_expr(negaxiom) << eom;
+    string_constraintt axiom_in_model(
+      univ_var, get(bound_inf), get(bound_sup), get(prem), get(body));
 
     satcheck_no_simplifiert sat_check;
     supert solver(ns, sat_check);
-    solver << negaxiom;
+    solver.set_ui(ui);
+    add_negation_of_constraint_to_solver(axiom_in_model, solver);
 
     switch(solver())
     {
     case decision_proceduret::D_SATISFIABLE:
       {
-        exprt val=solver.get(axiom.univ_var());
+        exprt val=solver.get(axiom_in_model.univ_var());
+        debug() << "string constraint can be violated for "
+                << axiom_in_model.univ_var().get_identifier()
+                << " = " << from_expr(val) << eom;
         violated[i]=val;
       }
       break;
@@ -606,11 +1191,10 @@ bool string_refinementt::check_axioms()
         exprt premise(axiom.premise());
         exprt body(axiom.body());
         implies_exprt instance(premise, body);
+        replace_expr(symbol_resolve, instance);
         replace_expr(axiom.univ_var(), val, instance);
-        if(seen_instances.insert(instance).second)
-          add_lemma(instance);
-        else
-          debug() << "instance already seen" << eom;
+        debug() << "adding counter example " << from_expr(instance) << eom;
+        add_lemma(instance);
       }
     }
 
@@ -682,13 +1266,13 @@ Function: string_refinementt::sum_over_map
 \*******************************************************************/
 
 exprt string_refinementt::sum_over_map(
-  std::map<exprt, int> &m, bool negated) const
+  std::map<exprt, int> &m, const typet &type, bool negated) const
 {
   exprt sum=nil_exprt();
   mp_integer constants=0;
   typet index_type;
   if(m.empty())
-    return nil_exprt();
+    return from_integer(0, type);
   else
     index_type=m.begin()->first.type();
 
@@ -723,12 +1307,20 @@ exprt string_refinementt::sum_over_map(
       default:
         if(second>1)
         {
-          for(int i=0; i<second; i++)
+          if(sum.is_nil())
+            sum=t;
+          else
+            plus_exprt(sum, t);
+          for(int i=1; i<second; i++)
             sum=plus_exprt(sum, t);
         }
-        else
+        else if(second<-1)
         {
-          for(int i=0; i>second; i--)
+          if(sum.is_nil())
+            sum=unary_minus_exprt(t);
+          else
+            sum=minus_exprt(sum, t);
+          for(int i=-1; i>second; i--)
             sum=minus_exprt(sum, t);
         }
       }
@@ -755,7 +1347,7 @@ Function: string_refinementt::simplify_sum
 exprt string_refinementt::simplify_sum(const exprt &f) const
 {
   std::map<exprt, int> map=map_representation_of_sum(f);
-  return sum_over_map(map);
+  return sum_over_map(map, f.type());
 }
 
 /*******************************************************************\
@@ -800,7 +1392,7 @@ exprt string_refinementt::compute_inverse_function(
   }
 
   elems.erase(it);
-  return sum_over_map(elems, neg);
+  return sum_over_map(elems, f.type(), neg);
 }
 
 
@@ -830,7 +1422,7 @@ Function: find_qvar
 
  Outputs: a Boolean
 
- Purpose: looks for the symbol and return true if it is found
+ Purpose: look for the symbol and return true if it is found
 
 \*******************************************************************/
 
@@ -885,6 +1477,26 @@ Function: string_refinementt::initial_index_set
           and the upper bound minus one
 
 \*******************************************************************/
+void string_refinementt::add_to_index_set(const exprt &s, exprt i)
+{
+  simplify(i, ns);
+  if(i.id()==ID_constant)
+  {
+    mp_integer mpi;
+    to_integer(i, mpi);
+    if(mpi<0)
+    {
+      debug() << "add_to_index_set : ignoring negative number " << mpi << eom;
+      return;
+    }
+  }
+  if(index_set[s].insert(i).second)
+  {
+    debug() << "adding to index set of " << from_expr(s)
+            << ": " << from_expr(i) << eom;
+    current_index_set[s].insert(i);
+  }
+}
 
 void string_refinementt::initial_index_set(const string_constraintt &axiom)
 {
@@ -906,8 +1518,7 @@ void string_refinementt::initial_index_set(const string_constraintt &axiom)
       // if cur is of the form s[i] and no quantified variable appears in i
       if(!has_quant_var)
       {
-        current_index_set[s].insert(i);
-        index_set[s].insert(i);
+        add_to_index_set(s, i);
       }
       else
       {
@@ -917,8 +1528,7 @@ void string_refinementt::initial_index_set(const string_constraintt &axiom)
           axiom.upper_bound(),
           from_integer(1, axiom.upper_bound().type()));
         replace_expr(qvar, kminus1, e);
-        current_index_set[s].insert(e);
-        index_set[s].insert(e);
+        add_to_index_set(s, e);
       }
     }
     else
@@ -952,12 +1562,7 @@ void string_refinementt::update_index_set(const exprt &formula)
       const exprt &i=cur.op1();
       assert(s.type().id()==ID_array);
       exprt simplified=simplify_sum(i);
-      if(index_set[s].insert(simplified).second)
-      {
-        debug() << "adding to index set of " << from_expr(s)
-                << ": " << from_expr(simplified) << eom;
-        current_index_set[s].insert(simplified);
-      }
+      add_to_index_set(s, simplified);
     }
     else
     {
@@ -1014,19 +1619,18 @@ exprt find_index(const exprt &expr, const exprt &str)
   catch (exprt i) { return i; }
 }
 
-
 /*******************************************************************\
 
 Function: string_refinementt::instantiate
 
-  Inputs: an universaly quantified formula `axiom`, an array of char
+  Inputs: a universally quantified formula `axiom`, an array of char
           variable `str`, and an index expression `val`.
 
- Outputs: substitute `qvar` the universaly quantified variable of `axiom`, by
+ Outputs: substitute `qvar` the universally quantified variable of `axiom`, by
           an index `val`, in `axiom`, so that the index used for `str` equals
           `val`. For instance, if `axiom` corresponds to
-          $\forall q. s[q+x]='a' && t[q]='b'$, `instantiate(axom,s,v)` would return
-          an expression for $s[v]='a' && t[v-x]='b'$.
+          $\forall q. s[q+x]='a' && t[q]='b'$, `instantiate(axom,s,v)`
+          would return an expression for $s[v]='a' && t[v-x]='b'$.
 
 \*******************************************************************/
 
@@ -1051,6 +1655,17 @@ exprt string_refinementt::instantiate(
   return implies_exprt(bounds, instance);
 }
 
+/*******************************************************************\
+
+Function: string_refinementt::instantiate_not_contains
+
+  Inputs: a quantified formula representing `not_contains`, and a
+          list to which to add the created lemmas to
+
+ Purpose: instantiate a quantified formula representing `not_contains`
+          by substituting the quantifiers and generating axioms
+
+\*******************************************************************/
 
 void string_refinementt::instantiate_not_contains(
   const string_not_contains_constraintt &axiom, std::list<exprt> &new_lemmas)
@@ -1102,3 +1717,76 @@ void string_refinementt::instantiate_not_contains(
       new_lemmas.push_back(witness_bounds);
     }
 }
+
+/*******************************************************************\
+
+Function: string_refinementt::substitute_array_lists()
+
+  Inputs: an expression containing array-list expressions
+
+ Outputs: an epression containing no array-list
+
+ Purpose: replace array-lists by 'with' expressions
+
+\*******************************************************************/
+
+exprt string_refinementt::substitute_array_lists(exprt expr) const
+{
+  for(size_t i=0; i<expr.operands().size(); ++i)
+  {
+    // TODO: only copy when necessary
+    exprt op(expr.operands()[i]);
+    expr.operands()[i]=substitute_array_lists(op);
+  }
+
+  if(expr.id()=="array-list")
+  {
+    assert(expr.operands().size()>=2);
+    typet &char_type=expr.operands()[1].type();
+    array_typet arr_type(char_type, infinity_exprt(char_type));
+    array_of_exprt new_arr(from_integer(0, char_type),
+                           arr_type);
+
+    with_exprt ret_expr(new_arr,
+                        expr.operands()[0],
+                        expr.operands()[1]);
+
+    for(size_t i=2; i<expr.operands().size()/2; i++)
+    {
+      ret_expr=with_exprt(ret_expr,
+                          expr.operands()[i*2],
+                          expr.operands()[i*2+1]);
+    }
+    return ret_expr;
+  }
+
+  return expr;
+}
+
+/*******************************************************************\
+
+Function: string_refinementt::get
+
+  Inputs: an expression
+
+ Outputs: an expression
+
+ Purpose: evaluation of the expression in the current model
+
+\*******************************************************************/
+
+exprt string_refinementt::get(const exprt &expr) const
+{
+  exprt ecopy(expr);
+  replace_expr(symbol_resolve, ecopy);
+  if(is_char_array(ecopy.type()))
+  {
+    auto it=found_length.find(ecopy);
+    if(it!=found_length.end())
+      return get_array(ecopy, it->second);
+  }
+
+  ecopy=supert::get(ecopy);
+
+  return substitute_array_lists(ecopy);
+}
diff --git a/src/solvers/refinement/string_refinement.h b/src/solvers/refinement/string_refinement.h
index be0cd332bc3..6688401f40c 100644
--- a/src/solvers/refinement/string_refinement.h
+++ b/src/solvers/refinement/string_refinement.h
@@ -2,7 +2,7 @@
 
 Module: String support via creating string constraints and progressively
         instantiating the universal constraints as needed.
-	The procedure is described in the PASS paper at HVC'13:
+        The procedure is described in the PASS paper at HVC'13:
         "PASS: String Solving with Parameterized Array and Interval Automaton"
         by Guodong Li and Indradeep Ghosh
 
@@ -14,6 +14,7 @@ Author: Alberto Griggio, alberto.griggio@gmail.com
 #define CPROVER_SOLVERS_REFINEMENT_STRING_REFINEMENT_H
 
 #include <util/string_expr.h>
+#include <util/replace_expr.h>
 #include <solvers/refinement/string_constraint.h>
 #include <solvers/refinement/string_constraint_generator.h>
 
@@ -27,30 +28,37 @@ Author: Alberto Griggio, alberto.griggio@gmail.com
 class string_refinementt: public bv_refinementt
 {
 public:
-  // refinement_bound is a bound on the number of refinement allowed
   string_refinementt(
-    const namespacet &_ns, propt &_prop, unsigned refinement_bound);
+    const namespacet &_ns,
+    propt &_prop,
+    unsigned refinement_bound);
 
   void set_mode();
 
   // Should we use counter examples at each iteration?
   bool use_counter_example;
 
-  virtual std::string decision_procedure_text() const
+  // Should we concretize strings when the solver finished
+  bool do_concretizing;
+
+  void set_max_string_length(int i);
+  void enforce_non_empty_string();
+  void enforce_printable_characters();
+
+  virtual std::string decision_procedure_text() const override
   {
     return "string refinement loop with "+prop.solver_text();
   }
 
   static exprt is_positive(const exprt &x);
 
+  exprt get(const exprt &expr) const override;
+
 protected:
   typedef std::set<exprt> expr_sett;
+  typedef std::list<exprt> exprt_listt;
 
-  virtual bvt convert_symbol(const exprt &expr);
-  virtual bvt convert_function_application(
-    const function_application_exprt &expr);
-
-  decision_proceduret::resultt dec_solve();
+  decision_proceduret::resultt dec_solve() override;
 
   bvt convert_bool_bv(const exprt &boole, const exprt &orig);
 
@@ -60,8 +68,14 @@ class string_refinementt: public bv_refinementt
 
   unsigned initial_loop_bound;
 
+  // Is the current model correct
+  bool concrete_model;
+
   string_constraint_generatort generator;
 
+  bool non_empty_string;
+  expr_sett nondet_arrays;
+
   // Simple constraints that have been given to the solver
   expr_sett seen_instances;
 
@@ -76,23 +90,44 @@ class string_refinementt: public bv_refinementt
   // Warning: this is indexed by array_expressions and not string expressions
   std::map<exprt, expr_sett> current_index_set;
   std::map<exprt, expr_sett> index_set;
+  replace_mapt symbol_resolve;
+  std::map<exprt, exprt_listt> reverse_symbol_resolve;
+  std::list<std::pair<exprt, bool>> non_string_axioms;
 
-  void display_index_set();
+  // Valuation in the current model of the symbols that have been created
+  // by the solver
+  replace_mapt current_model;
 
-  void add_lemma(const exprt &lemma, bool add_to_index_set=true);
+  void add_equivalence(const irep_idt & lhs, const exprt & rhs);
 
-  bool boolbv_set_equality_to_true(const equal_exprt &expr);
+  void display_index_set();
 
-  literalt convert_rest(const exprt &expr);
+  void add_lemma(const exprt &lemma,
+                 bool simplify=true,
+                 bool add_to_index_set=true);
 
-  void add_instantiations();
+  exprt substitute_function_applications(exprt expr);
+  typet substitute_java_string_types(typet type);
+  exprt substitute_java_strings(exprt expr);
+  exprt substitute_array_with_expr(exprt &expr, exprt &index) const;
+  exprt substitute_array_access(exprt &expr) const;
+  void add_symbol_to_symbol_map(const exprt &lhs, const exprt &rhs);
+  bool is_char_array(const typet &type) const;
+  bool add_axioms_for_string_assigns(const exprt &lhs, const exprt &rhs);
+  void set_to(const exprt &expr, bool value) override;
 
+  void add_instantiations();
+  void add_negation_of_constraint_to_solver(
+    const string_constraintt &axiom, supert &solver);
+  void fill_model();
   bool check_axioms();
 
+  void set_char_array_equality(const exprt &lhs, const exprt &rhs);
   void update_index_set(const exprt &formula);
   void update_index_set(const std::vector<exprt> &cur);
   void initial_index_set(const string_constraintt &axiom);
   void initial_index_set(const std::vector<string_constraintt> &string_axioms);
+  void add_to_index_set(const exprt &s, exprt i);
 
   exprt instantiate(
     const string_constraintt &axiom, const exprt &str, const exprt &val);
@@ -101,17 +136,28 @@ class string_refinementt: public bv_refinementt
     const string_not_contains_constraintt &axiom,
     std::list<exprt> &new_lemmas);
 
+  exprt substitute_array_lists(exprt) const;
+
   exprt compute_inverse_function(
     const exprt &qvar, const exprt &val, const exprt &f);
 
   std::map<exprt, int> map_representation_of_sum(const exprt &f) const;
-  exprt sum_over_map(std::map<exprt, int> &m, bool negated=false) const;
+  exprt sum_over_map(
+    std::map<exprt, int> &m, const typet &type, bool negated=false) const;
 
   exprt simplify_sum(const exprt &f) const;
 
-  exprt get_array(const exprt &arr, const exprt &size);
+  void concretize_string(const exprt &expr);
+  void concretize_results();
+  void concretize_lengths();
+
+  // Length of char arrays found during concretization
+  std::map<exprt, exprt> found_length;
+
+  exprt get_array(const exprt &arr, const exprt &size) const;
+  exprt get_array(const exprt &arr) const;
 
-  std::string string_of_array(const exprt &arr, const exprt &size) const;
+  std::string string_of_array(const array_exprt &arr);
 };
 
 #endif
diff --git a/src/util/Makefile b/src/util/Makefile
index fefabaed3af..0bfb2539af4 100644
--- a/src/util/Makefile
+++ b/src/util/Makefile
@@ -23,7 +23,9 @@ SRC = arith_tools.cpp base_type.cpp cmdline.cpp config.cpp symbol_table.cpp \
       memory_info.cpp pipe_stream.cpp irep_hash.cpp endianness_map.cpp \
       ssa_expr.cpp json_irep.cpp json_expr.cpp \
       fresh_symbol.cpp \
-      string_utils.cpp
+      string_utils.cpp \
+      refined_string_type.cpp \
+      #Empty last line
 
 INCLUDES= -I ..
 
diff --git a/src/util/irep_ids.txt b/src/util/irep_ids.txt
index 066a5f831cc..470a0f01c78 100644
--- a/src/util/irep_ids.txt
+++ b/src/util/irep_ids.txt
@@ -743,6 +743,7 @@ string_constraint
 string_not_contains_constraint
 cprover_char_literal_func
 cprover_string_literal_func
+cprover_string_array_of_char_pointer_func
 cprover_string_char_at_func
 cprover_string_char_set_func
 cprover_string_code_point_at_func
diff --git a/src/util/refined_string_type.cpp b/src/util/refined_string_type.cpp
new file mode 100644
index 00000000000..0625149cf83
--- /dev/null
+++ b/src/util/refined_string_type.cpp
@@ -0,0 +1,51 @@
+/********************************************************************\
+
+Module: Type for string expressions used by the string solver.
+        These string expressions contain a field `length`, of type
+        `index_type`, a field `content` of type `content_type`.
+        This module also defines functions to recognise the C and java
+        string types.
+
+Author: Romain Brenguier, romain.brenguier@diffblue.com
+
+\*******************************************************************/
+
+#include <util/cprover_prefix.h>
+
+#include "refined_string_type.h"
+
+/*******************************************************************\
+
+Constructor: refined_string_typet::refined_string_typet
+
+     Inputs: type of characters
+
+\*******************************************************************/
+
+refined_string_typet::refined_string_typet(
+  const typet &index_type, const typet &char_type)
+{
+  infinity_exprt infinite_index(index_type);
+  array_typet char_array(char_type, infinite_index);
+  components().emplace_back("length", index_type);
+  components().emplace_back("content", char_array);
+  set_tag(CPROVER_PREFIX"refined_string_type");
+}
+
+/*******************************************************************\
+
+Function: refined_string_typet::is_refined_string_type
+
+  Inputs: a type
+
+ Outputs: Boolean telling whether the input is a refined string type
+
+\*******************************************************************/
+
+bool refined_string_typet::is_refined_string_type(const typet &type)
+{
+  return
+    type.id()==ID_struct &&
+    to_struct_type(type).get_tag()==CPROVER_PREFIX"refined_string_type";
+}
+
diff --git a/src/solvers/refinement/refined_string_type.h b/src/util/refined_string_type.h
similarity index 55%
rename from src/solvers/refinement/refined_string_type.h
rename to src/util/refined_string_type.h
index 3ecc0ac3a9f..a0cb7500e7f 100644
--- a/src/solvers/refinement/refined_string_type.h
+++ b/src/util/refined_string_type.h
@@ -10,8 +10,8 @@ Author: Romain Brenguier, romain.brenguier@diffblue.com
 
 \*******************************************************************/
 
-#ifndef CPROVER_SOLVERS_REFINEMENT_REFINED_STRING_TYPE_H
-#define CPROVER_SOLVERS_REFINEMENT_REFINED_STRING_TYPE_H
+#ifndef CPROVER_UTIL_REFINED_STRING_TYPE_H
+#define CPROVER_UTIL_REFINED_STRING_TYPE_H
 
 #include <util/std_types.h>
 #include <util/std_expr.h>
@@ -33,41 +33,16 @@ class refined_string_typet: public struct_typet
 
   const typet &get_char_type() const
   {
-    assert(components().size()==2);
-    return components()[0].type();
+    return get_content_type().subtype();
   }
 
   const typet &get_index_type() const
   {
-    return get_content_type().size().type();
-  }
-
-  // For C the unrefined string type is __CPROVER_string, for java it is a
-  // pointer to a struct with tag java.lang.String
-
-  static bool is_c_string_type(const typet &type);
-
-  static bool is_java_string_pointer_type(const typet &type);
-
-  static bool is_java_string_type(const typet &type);
-
-  static bool is_java_string_builder_type(const typet &type);
-
-  static bool is_java_char_sequence_type(const typet &type);
-
-  static bool is_unrefined_string_type(const typet &type)
-  {
-    return (
-      is_c_string_type(type) ||
-      is_java_string_pointer_type(type) ||
-      is_java_string_builder_type(type) ||
-      is_java_char_sequence_type(type));
+    assert(components().size()==2);
+    return components()[0].type();
   }
 
-  static bool is_unrefined_string(const exprt &expr)
-  {
-    return (is_unrefined_string_type(expr.type()));
-  }
+  static bool is_refined_string_type(const typet &type);
 
   constant_exprt index_of_int(int i) const
   {
@@ -75,9 +50,10 @@ class refined_string_typet: public struct_typet
   }
 };
 
-const refined_string_typet &to_refined_string_type(const typet &type)
+extern inline const refined_string_typet &to_refined_string_type(
+  const typet &type)
 {
-  assert(type.id()==ID_struct);
+  assert(refined_string_typet::is_refined_string_type(type));
   return static_cast<const refined_string_typet &>(type);
 }
 
diff --git a/src/util/std_expr.h b/src/util/std_expr.h
index a2f78ab25e8..7debf8d7e62 100644
--- a/src/util/std_expr.h
+++ b/src/util/std_expr.h
@@ -3450,6 +3450,19 @@ class function_application_exprt:public exprt
     operands().resize(2);
   }
 
+  explicit function_application_exprt(const typet &_type):
+    exprt(ID_function_application, _type)
+  {
+    operands().resize(2);
+  }
+
+  function_application_exprt(
+    const symbol_exprt &_function, const typet &_type):
+      function_application_exprt(_type)
+  {
+    function()=_function;
+  }
+
   exprt &function()
   {
     return op0();