This dead lock has also to do with another issue I'm investigating, not necessarily with Valves but with the behavior on failover itself. It looks like ACK is called as soon as the message arrives on MessageCallbackHandler, what might be causing the reference to be deleted. In case of a failure, the buffer is being cleared at this point, and we will call redeliveries, but as the message was previously acknowledged already it won't exist on the channel, what will cause an exception on ChannelSupport::recoverDeliveries. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3996314#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...