The JMS server failed over, which is an abnormal situation. It's appropriate for code that functions as a JMS client to log a WARN or even an ERROR about this. The integration layer that MDB's use to connect to the JMS server deal with the situation by automatically reconnecting to the new JMS server once it has started. I believe (but am not sure) that if you obtains connections through the JMS resource adapter (i.e. java:/JmsXA) you get automatic reconnect behavior as well. If you see WARN/ERROR messages in the log for a brief period during server failover, that's normal. If they continue after the new JMS server is operating, that's a problem. In some earlier AS releases, the severity level of some logging messages during the failover was higher than necessary (although some WARN/ERROR logging is appropriate.) I believe those issues were fixed in 4.0.3. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4007848#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...