Websocket - ServerEndpoint and ClientEndpoint does not exchange messages

Question

I'm currently testing Websockets with Glassfish 4 and the "on board" implementation but cannot send or receive any messages although following tutorials like The Java EE 7 Tutorial - Sending and Receiving Messages or How to build Java WebSocket Applications Using the JSR 356 API. I want to implement a simple client server communication so all I have is a

server:

@ServerEndpoint("/echotest")
public class Server {
    private static final Logger LOGGER = LoggerFactory.getLogger(Server.class);

    @OnOpen
    public void onOpen(Session session) {
        LOGGER.info("OnOpen invoked by Session '{}'.", session.getId());

        try {
            session.getBasicRemote().sendText("Hello Client!");
        } catch (IOException ex) {
            LOGGER.error("Message delivery failed.", ex);
        }
    }

    @OnClose
    public void onClose(Session session, CloseReason closeReason) {
        LOGGER.info("OnClose invoked by Session '{}'; Reason: {}.", session.getId(), closeReason.getReasonPhrase());
    }

    @OnMessage
    public void onMessage(Session session, String msg) {
        LOGGER.info("OnMessage invoked by Session '{}'; Message: {}.", session.getId(), msg);
    }
}

and a client:

@ClientEndpoint
public class Client {

    private static CountDownLatch latch;
    private static final Logger LOGGER = LoggerFactory.getLogger(Client.class);

    @OnOpen
    public void onOpen(Session session) {
        LOGGER.info("OnOpen invoked by Session '{}'.", session.getId());

        try {
            session.getBasicRemote().sendText("Hello Server!");
        } catch (IOException ex) {
            LOGGER.error("Message delivery failed.", ex);
        }
    }

    @OnClose
    public void onClose(Session session, CloseReason closeReason) {
        LOGGER.info("OnClose invoked by Session '{}'; Reason: {}.", session.getId(), closeReason.getReasonPhrase());
    }

    @OnMessage
    public void onMessage(Session session, String msg) {
        LOGGER.info("OnMessage invoked by Session '{}'; Message: {}.", session.getId(), msg);
    }

    public static void main(String[] args) {
        latch = new CountDownLatch(1);

        WebSocketContainer container = ContainerProvider.getWebSocketContainer();
        try {
            container.connectToServer(Client.class, new URI("ws://localhost:8080/Tstr/echotest"));
            latch.await();

        } catch (DeploymentException | URISyntaxException | InterruptedException | IOException e) {
            LOGGER.error("Connection error occured!", e);
        }
    }
}

The Websocket is available and I can connect to the server (changing the URI leads to a 404 handsheak error) but none of the (server sided) methods will be invoked and the only log message I'm getting is:

INFO: OnOpen invoked by Session 'acc92925-6682-4414-9e78-cf60a624b014'.

on the client side. I would expect the server to at least log the onOpen invokation. Using an (untouched) Glassfish 4 with Netbeans 8 for this test.

Any suggestions why there are no messages exchanged?

Answer 1

Your code works for me, however I had to replace Logger (slf4j?) with this one java.util.logging.Logger