public class SomeBoundedService extends Service {

  class SomeHandler extends Handler {
    @Override
    public void handleMessage(Message message) {
      switch (msg.arg1) {
        // ...
        default:
          super.handleMessage(message);
      }
    }
  }
  
  final Messenger messenger = new Messenger(new SomeHandler());

  @Override
  public IBinder onBind(Intent intent) {
    return messenger.getBinder();
  }
}