Consuming JMS ObjectMessages

Question

Hi!
I have the following code that is meant to run through a loop until no more objectmessages are in the jms queue.
Messages are being correctly sent to the jms queue(to test this, i have replaced "receiveNoWait()" with receive() and "Reached here" is been printed to the screen for each object received, but loop does not break) but the loop is always breaking.
Can you help me fix this?
Thanks for your help in advance.
Context jndiContext = new InitialContext();
ConnectionFactory factory =(ConnectionFactory) jndiContext.lookup("jms/ConnectionFactory");
Destination dest = (Destination) jndiContext.lookup("jms/Queue");               connection = factory.createConnection();
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);     
MessageConsumer consumer = session.createConsumer(dest);connection.start();
while (true){
     ObjectMessage m = (ObjectMessage consumer.receiveNoWait();
     if(m == null)
     break;
     System.out.println("Reached here");          
     }

Answer 1

If you want to drain a queue and be completely sure you get every possible message I'd recommend using the receive(timeout) method with some timeout of a second or two. This is because many JMS providers will make sure receiveNoWait() does not block at all - but that does not always mean that there is not a message on the queue. JMS is designed for high performance with as little blocking and latency as possible - providers typically do things asynchronously, so receiveNoWait() often just means there is no message available in this JVM; not that there is no message on the broker available.
receive(1000) will typically wait long enough to drain messages from the queue if they are available. Its kinda JMS provider dependent; but most providers should work with receive(1000); many won't for receiveNoWait()
James
http://logicblaze.com/