Android JavaでWebSocketを使う

http://www.elabs.se/blog/66-using-websockets-in-native-ios-and-android-apps
Java-WebSocketを使う
https://github.com/TooTallNate/Java-WebSocket
gradle

dependencies {
  compile "org.java-websocket:Java-WebSocket:1.3.0"
}

private void connectWebSocket() {
  URI uri;
  try {
    uri = new URI("ws://websockethost:8080");
  } catch (URISyntaxException e) {
    e.printStackTrace();
    return;
  }

  mWebSocketClient = new WebSocketClient(uri) {
    @Override
    public void onOpen(ServerHandshake serverHandshake) {
      Log.i("Websocket", "Opened");
      mWebSocketClient.send("Hello from " + Build.MANUFACTURER + " " + Build.MODEL);
    }

    @Override
    public void onMessage(String s) {
      final String message = s;
      runOnUiThread(new Runnable() {
        @Override
        public void run() {
          TextView textView = (TextView)findViewById(R.id.messages);
          textView.setText(textView.getText() + "\n" + message);
        }
      });
    }

    @Override
    public void onClose(int i, String s, boolean b) {
      Log.i("Websocket", "Closed " + s);
    }

    @Override
    public void onError(Exception e) {
      Log.i("Websocket", "Error " + e.getMessage());
    }
  };
  mWebSocketClient.connect();
}