WebSocket.java

package parent;

import java.io.IOException;
import java.net.URI;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import javax.websocket.ClientEndpointConfig;
import javax.websocket.Endpoint;
import javax.websocket.EndpointConfig;
import javax.websocket.MessageHandler;
import javax.websocket.Session;

import org.glassfish.tyrus.client.ClientManager;
import org.glassfish.tyrus.container.jdk.client.JdkClientContainer;

public class Main {
	
	private static CountDownLatch messageLatch;

	public static void main(String[] args) throws IOException {
		try {
            messageLatch = new CountDownLatch(1);
            ClientManager client = ClientManager.createClient(JdkClientContainer.class.getName());
            client.connectToServer(new Endpoint() {
                @Override
                public void onOpen(Session session, EndpointConfig config) {
                    try {
                        session.addMessageHandler(new MessageHandler.Whole<String>() {
                            @Override
                            public void onMessage(String message) {
                                System.out.println("Received message: "+message);
                                messageLatch.countDown();
                            }
                        });
                        session.getBasicRemote().sendText("155-questions-active");
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }, ClientEndpointConfig.Builder.create().build(), new URI("wss://qa.sockets.stackexchange.com/"));
            messageLatch.await(100, TimeUnit.SECONDS);
        } catch (Exception e) {
            e.printStackTrace();
        }
	}

}