private static void emitSetThreadCallbacks(ClassEmitter ce) {
    CodeEmitter e = ce.begin_method(Constants.ACC_PUBLIC | Constants.ACC_STATIC,
                                    SET_THREAD_CALLBACKS,
                                    null);
    e.getfield(THREAD_CALLBACKS_FIELD);
    e.load_arg(0);
    e.invoke_virtual(THREAD_LOCAL, THREAD_LOCAL_SET);
    e.return_value();
    e.end_method();
  }
private static void emitSetThreadCallbacks(ClassEmitter ce)