i'm guessing at this point, but could it be that your temp storage/memory storage for non persistent messages is exhausted? the default config of activemq in this case is to block the message add until the message can be added to the destination.
-- View this message in context: http://activemq.2283324.n4.nabble.com/Why-would-my-producer-hang-on-a-broker-that-can-t-persist-tp3906444p3911470.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.