private void emitSetCallbacks(ClassEmitter ce) {
    CodeEmitter e = ce.begin_method(Constants.ACC_PUBLIC, SET_CALLBACKS, null);
    e.load_this();
    e.load_arg(0);
    for (int i = 0; i < callbackTypes.length; i++) {
      e.dup2();
      e.aaload(i);
      e.checkcast(callbackTypes[i]);
      e.putfield(getCallbackField(i));
    }
    e.return_value();
    e.end_method();
  }
private void emitSetCallbacks(ClassEmitter ce)