private byte[] calculateFrames(byte[] source) {
ClassReader rc = new ClassReader(source);
ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
// Adjust Version to 1.6 to enable frames:
rc.accept(new ClassAdapter(cw) {
@Override
public void visit(int version, int access, String name,
String signature, String superName, String[] interfaces) {
super.visit(Opcodes.V1_6, access, name, signature, superName,