Messages not making it to the jms queue...

Question

We are having an interesting problem. AFter a fresh restart of our instnace, it will process a message fine. but, if we wait a few minutes, try another post, the message doesn't get put ot the queue, and it basically hangs the instance.
          I am not sure how to trouble shoot this since there are no errors sent to the logs. the console will show a stuckthread message eventually.
          I was wondering if anyone could help with what are some potential causes, and if there is anyway to get additional information out of the server. I have turned on the debug and set the level to info, but no additional information is getting generated.
          We've done print outs in the code right up to where the failure occurs.
          I"ve posted the code snippet that is being used. It failes when it gets to the code after GQ 5.
          Any help is appreicated.
          public boolean queueMessage(Serializable messageObj, String queueName)
          throws NamingException, JMSException, ResourceKeeperException, Exception {
          EventLogger.log(Level.DEBUG, "Trying to put a message in the " + queueName + " queue in GenericQueue.queueMessage(): ");
          try {
          if (messageObj != null)
          EventLogger.log(Level.DEBUG, "Serializable messageObj in GenericQueue.queueMessage(): " + messageObj.toString());
          else
          EventLogger.log(Level.DEBUG, "messageObj is not serializable");
          Hashtable ht = null;
          boolean inHash = false;
          //check to see if the queue is in the hashtable
          if (queues.containsKey(queueName)) {
          EventLogger.log(Level.DEBUG, "The Queue was in the hashTable in GenericQueue.queueMessage(): ");
          inHash = true;
          ht = (Hashtable) queues.get(queueName);
          else EventLogger.log(Level.DEBUG,"The Queue was not the hashTable using default values in GenericQueue.queueMessage(): ");
          Context ctx = InitialContext.getInitialContext();
          EventLogger.log(Level.DEBUG, "GQ 1");
          QueueConnectionFactory qconFactory = null;
          EventLogger.log(Level.DEBUG, "GQ 2");
          if (inHash)
          qconFactory = (QueueConnectionFactory) ctx.lookup((String) ht.get("jmsFactory"));
          EventLogger.log(Level.DEBUG, "GQ 3");
          else
          EventLogger.log(Level.DEBUG, "GQ 4");
          qconFactory = (QueueConnectionFactory) ctx.lookup(jmsFactory);
          EventLogger.log(Level.DEBUG, "GQ 5");
          QueueConnection qcon = qconFactory.createQueueConnection();
          EventLogger.log(Level.DEBUG, "GQ 6");
          QueueSession qsession = qcon.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);
          EventLogger.log(Level.DEBUG, "GQ 7");
          QueueSender qsender;
          EventLogger.log(Level.DEBUG, "GQ 8");
          Queue queue;
          EventLogger.log(Level.DEBUG, "GQ 9");
          queue = (Queue) ctx.lookup(queueName);

Answer 1

The "stuck thread" message is likely a good clue. Force a server thread dump when this occurs. Feel free to post the thread dump here.
          Side note: Make sure the "GenericQueue" method doesn't attempt to multi-thread access to any JMS session, consumer, or producer.
          Tom