Reapply "Java: Fix cartesian product"

This reverts commit c1654ce.

Author: atorralba

java/ql/src/Advisory/Documentation/ImpossibleJavadocThrows.ql

@@ -16,21 +16,14 @@ RefType getTaggedType(ThrowsTag tag) {
   exists(ImportType i | i.getFile() = tag.getFile() | i.getImportedType() = result)
 }
 
-predicate canThrow(Callable callable, RefType exception) {
-  exists(string uncheckedException |
-    uncheckedException = "RuntimeException" or uncheckedException = "Error"
-  |
-    exception.getAnAncestor().hasQualifiedName("java.lang", uncheckedException)
-  )
-  or
-  callable.getAnException().getType().getADescendant() = exception
-}
-
-from ThrowsTag throwsTag, RefType thrownType, Callable docMethod
+// Uses ClassOrInterface as type for thrownType to also cover case where erroneously an interface
+// type is declared as thrown exception
+from ThrowsTag throwsTag, ClassOrInterface thrownType, Callable docMethod
 where
   getTaggedType(throwsTag) = thrownType and
   docMethod.getDoc().getJavadoc().getAChild*() = throwsTag and
-  not canThrow(docMethod, thrownType)
+  not thrownType instanceof UncheckedThrowableType and
+  not docMethod.getAnException().getType().getADescendant() = thrownType
 select throwsTag,
   "Javadoc for " + docMethod + " claims to throw " + thrownType.getName() +
     " but this is impossible."