The Lurker

My favourite JBoss error

posted by ajf on 2003-08-08 at 12:05 pm

11:47:16,769 ERROR [JMSContainerInvoker] Exception in JMSCI message listener

javax.ejb.EJBException: Unexpected Error

java.lang.ClassCircularityError: au/edu/educationau/belts/util/ServiceUtilities

ClassCircularityError, according to the documentation, means that "a class or interface could not be loaded because it would be its own superclass or superinterface". It's not clear to me how this could be true of a class which extends java.lang.Object and implements no interfaces. Perhaps it's just a really worthless error message, and the ServiceUtilities class could not be loaded because some other class it refers to has a problem?

I often see this message once or twice relating to our use message-driven beans, but they go away a short time later, even though nothing to do with classes available to the system has changed. I just don't get it.

Meanwhile, browsing source code of the JMSContainerInvoker class, I notice that it has an inner class called MessageListenerImpl, which has a constructor with a JMSContainerInvoker class as a parameter. The class is instantiated with the expression new MessageListenerImpl(this) from the JMSContainerInvoker's innerCreate() method, which suggests that its author didn't quite understand inner classes at the time. Oh well.