Is the subscriber using the message listener, when a message is published, to receive the message and remove it from the topic. Will the subscriber be able to receive another message from a publisher on the same topic. At the moment i have developed an mdb,publisher and subscriber and i receive only the first message without any listener whatsoever. However if i add the following line: subscriber.setMessageListener(this); i get the following exception: javax.jms.JMSException: A message listener is already registered. My class implements MessageListener and onMessage method. Any ideas?