code: public static void callStringBuilderToString(CodeBuilder b) {
          // Because of JDK1.5 bug which exposes AbstractStringBuilder class,
          // cannot use reflection to get method signature.
          TypeDesc stringBuilder = TypeDesc.forClass(StringBuilder.class);
          b.invokeVirtual(stringBuilder, "toString", TypeDesc.STRING, null);
      }
docs: Calls toString on a StringBuilder. A StringBuilder must be on the stack,
  and a String is left on the stack after the call.