Message handling in onMessage WebSocket

I'm trying to implement a WebSocket client.

My code is here:

import org.json.JSONObject;
import javax.websocket.*;
import java.io.IOException;
public class MyClientEndpoint extends Endpoint {
private Session session;

@Override
public void onOpen(Session session, EndpointConfig endpointConfig) {
    System.out.println("Web socket opened");
    this.session = session;
    this.session.addMessageHandler(new MessageHandler.Whole<String>() {

        public void onMessage(String message) {
            System.out.println("!!!!!!!!!!!!!!! Retrieved: " + message);
            JSONObject jsonResponse = new JSONObject(message);
            String user = jsonResponse.get("user").toString();
            System.out.println("!!!!!!!!!!!!!!! The User: " + user);
        }
    });
}

public void sendMessage(String message) throws IOException {
    this.session.getBasicRemote().sendText(message);
}
}

The problem comes in onMessage(String message) method, because after the message is printed it seems that I can not process the message in order to create the String user object. How I can implement this?

I am using Glassfish Tyrus.

Thank you!

I've found where the problem was. In JSONObject that I've created, the user key is not on the first row, so I must take another key in order to have access to the user key. The problem is that when I try to access the user key I'm not receiveing any exception.