Messages left on the queue when using a transacted session.

[Robert Nicholson]

So, I have a pretty standard JMS message listener but when using  
ActiveMQ it often just doesn't receive any messages even when there  
are messages on the queue. The Session is a transacted one with  
AUTO_ACKNOWLEDGE but for some reason the messages are never taken off  
the queue.

I believe AUTO_ACKNOWLEDGE is ignored and eventually it says  
SESSION_TRANSACTED but what I don't understand is upon committing the  
session the messages are still on the queue.

Why is that?