Currently we have implemented the queue browser to iterate over the set of all undelivered + delivered but not yet acknowledged messages in a queue. I don't see anything particularly wrong with this, but neither can I see anything in the JMS spec that says the iteration has to include the set of delivered but not yet unacknowledged methods. The reason I bring this up is that I would like to remove the set of deliveries which are currently managed in ChannelSupport. For primary JMS use cases: delivery, acknowledgement, cancellation it is not necessary for the channel to maintain a delivery set. Removing it would greatly simplify the code and probably improve performance and reduce scope for race conditions. If we can relax the queue browsing implementation to not include delivered but not yet acked messages then we can do this, otherwise it would be more difficult. My view is we shouldn't sacrifice performance and simplicity for a non primary use case (browsing) which is generally used for management. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3994690#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...