diff --git a/jbmc/src/java_bytecode/java_bytecode_parse_tree.h b/jbmc/src/java_bytecode/java_bytecode_parse_tree.h
index 44230ec2064..3bd1a6deafc 100644
--- a/jbmc/src/java_bytecode/java_bytecode_parse_tree.h
+++ b/jbmc/src/java_bytecode/java_bytecode_parse_tree.h
@@ -86,7 +86,8 @@ struct java_bytecode_parse_treet
   struct methodt : public membert
   {
     irep_idt base_name;
-    bool is_native, is_abstract, is_synchronized, is_bridge, is_varargs;
+    bool is_native = false, is_abstract = false, is_synchronized = false,
+         is_bridge = false, is_varargs = false;
     source_locationt source_location;
 
     typedef std::vector<instructiont> instructionst;
diff --git a/jbmc/src/java_bytecode/java_string_library_preprocess.cpp b/jbmc/src/java_bytecode/java_string_library_preprocess.cpp
index bae9a3db4e3..bc26b7444c7 100644
--- a/jbmc/src/java_bytecode/java_string_library_preprocess.cpp
+++ b/jbmc/src/java_bytecode/java_string_library_preprocess.cpp
@@ -33,7 +33,7 @@ Date:   April 2017
 
 /// \return tag of a struct prefixed by "java::" or symbolic tag
 /// empty string if not symbol or struct
-irep_idt get_tag(const typet &type)
+static irep_idt get_tag(const typet &type)
 {
   /// \todo Use follow instead of assuming tag to symbol relationship.
   if(type.id() == ID_symbol_type)
@@ -169,7 +169,7 @@ bool java_string_library_preprocesst::is_java_char_array_pointer_type(
 }
 
 /// \return the type of the length field in java Strings.
-typet string_length_type()
+static typet string_length_type()
 {
   return java_int_type();
 }