Messages get lost on WebLogic WebSocket connection

Question

I implemented a JMS Client that is supposed to update the browser when a JMS Message arrives. Unfortunately, about 50 per cent of the messages are lost and never arrive. It is really strange. What could be the reason?

Here I post part of my code. I created the client according to the html5 websocket examples for weblogic and I have version 12.1.2. I have no errors on java nor on javascript side. The console prints Receive message from Bean: Shit happens ist printed every two seconds, but I receive only on the client every 4 seconds or even less. Why is that?

package com.packtpub.techbuzz.jms;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import javax.jms.JMSException;
import javax.jms.MessageListener;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueReceiver;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import weblogic.websocket.ClosingMessage;
import weblogic.websocket.WebSocketAdapter;
import weblogic.websocket.WebSocketConnection;
import weblogic.websocket.WebSocketListener;
import weblogic.websocket.annotation.WebSocket;
@WebSocket(timeout = -1, pathPatterns = "/counter.ws")
public class SocketMediator extends WebSocketAdapter implements WebSocketListener, MessageListener { 
 private static SocketMediator sm; 
 public final static String JNDI_FACTORY = "weblogic.jndi.WLInitialContextFactory";
 public final static String JMS_FACTORY = "jms/myConnectionFactory"; 
 private static final String RETURN_QUEUE = "jms/TestJMSReturnQueue"; 
 private static final String QUEUE = "jms/myTestQueue"; 
 private QueueConnectionFactory qconFactory; 
 private QueueConnection qcon; 
 private QueueSession qsession; 
 private QueueReceiver qreceiver; 
 private QueueSender qsender; 
 private javax.jms.Queue queueReturn; 
 private javax.jms.Queue queue; 
 private boolean isConnected; 
 public static SocketMediator getSm() { 
 return sm; 
 } 
 public SocketMediator() { 
 super(); 
 sm = this; 
 isConnected = false; 
 try { 
 InitialContext ctx = new InitialContext(); 
 qconFactory = (QueueConnectionFactory) ctx.lookup(JMS_FACTORY); 
 qcon = qconFactory.createQueueConnection(); 
 qsession = qcon.createQueueSession(false, Session.AUTO_ACKNOWLEDGE); 
 queue = (javax.jms.Queue) ctx.lookup(QUEUE); 
 qreceiver = qsession.createReceiver(queue); 
 qreceiver.setMessageListener(this); 
 qsender = qsession.createSender(queue); 
 qcon.start(); 
 isConnected = true; 
 int counter = 0;
 // Use the ThreadScheduledExecutor to invoke a runnable at a later time 
 // which posts some data into the queue
 Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate(
 new Runnable() {
 @Override
 public void run() {
 try {
 try {
 TextMessage textMessage = qsession.createTextMessage("Shit happens"); 
 qsender.send(textMessage);
 } catch (JMSException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 } catch (Exception ex) {
 }
 }
 }, 2, 1, TimeUnit.SECONDS);
 } catch (JMSException e) { 
 e.printStackTrace(); 
 } catch (NamingException e) { 
 e.printStackTrace(); 
 } 
 } 
 @Override 
 public void onOpen(WebSocketConnection webSocketConnection) { 
 System.out.println("New connection was created from a client " + webSocketConnection.getRemoteAddress()); 
 super.onOpen(webSocketConnection); 
 } 
 @Override 
 public void onMessage(WebSocketConnection connection, String payload) { 
 // Sends message from the browser back to the client. 
 System.out.println("Does this ever actually fire?");
 } 
 @Override 
 public void onClose(WebSocketConnection webSocketConnection, ClosingMessage closingMessage) { 
 super.onClose(webSocketConnection, closingMessage); 
 System.out.println("Connection was closed from a client " + webSocketConnection.getRemoteAddress()); 
 } 
 @Override 
 public void onError(WebSocketConnection webSocketConnection, Throwable throwable) { 
 super.onError(webSocketConnection, throwable); 
 System.out.println("Something went seriously wrong with client " + webSocketConnection.getRemoteAddress()); 
 } 
 // Subscription for return messages 
 @Override 
 public void onMessage(javax.jms.Message msg) { 
 final String msgText;
 try { 
 if (msg instanceof TextMessage) {
 msgText = ((TextMessage) msg).getText();
 } else {
 msgText = msg.toString();
 }
 System.out.println("Received message from bean: "+msgText); 
 for(final WebSocketConnection conn : getWebSocketContext().getWebSocketConnections()){ 
 Executors.newSingleThreadScheduledExecutor().schedule(
 new Runnable() {
 @Override
 public void run() {
 try {
 conn.send(msgText); 
 } catch (Exception ex) {
 }
 }
 }, 1, TimeUnit.SECONDS);
 } 
 } catch (JMSException e) { 
 e.printStackTrace(); 
 } 
 } 
} 

• Gimby: Do I need to interpret "about 50 per cent of the messages are lost and never arrive" as "about 50 per cent of the time the onMessage() handler doesn't get fired" ? Or did you actually investigate the queue?
• Zeus: Check if you have a cluster setup, if so, the messages might be going to the other servers queue. You need to setup Messaging bridge in that case to resolve it.
• Will Lovett: I had the same problem if I redeployed my application without shutting down the WebLogic server. I HAVE to follow these steps ... 1) Undeploy the app. 2) Restart the server 3) Redeploy the app. If I don't, I'll only get 50% of my messages. I have code just like yours.
• Will Lovett: Something else ... you may want to think about setting up a TopicReceiver as opposed to a Queue. The first instance of your SocketMediator will acknowledge the receipt, but I don't think the rest will.
• Will Lovett: Haha, when I said I have code just like yours. It looks like you found my post: community.oracle.com/thread/3543318