If a Jakarta Messaging provider detects a serious problem with a Connection object, it informs the Connection object's ExceptionListener, if one has been registered. It does this by calling the listener's onException method, passing it a JMSException argument describing the problem.

An exception listener allows a client to be notified of a problem asynchronously. Some connections only consume messages, so they would have no other way to learn that their connection has failed.

A Jakarta Messaging provider should attempt to resolve connection problems itself before it notifies the client of them.