WebRTCDataChannelSnippet.java

    public class ObserverX implements Observer{
        @Override
        public void onStateChange(){
            System.out.println("data received");
        }
        @Override
        public void onMessage(Buffer buffer){
            System.out.println(buffer.toString());
        }
    }

    @Override
    public void onDataChannel(DataChannel dataChannel) {
        ObserverX tx = new ObserverX();
        dataChannel.registerObserver(tx);
    }