The last two days have been spent on one problem. A web service deployed on Axis 2 as an AAR module worked fine with Weblogic. It broke horribly on JBoss.

The solution turned out to be sticking the JAXB2, Activation and JMS libraries in the JBoss endorsed library directory. This is really, really bad. It's not (probably) too much of a problem for our application, as we're the only thing running on the server, but suddenly our modules are getting horribly polluted by rubbish up the tree. And since some of our older modules use JAXB1, this fast becomes painful.

Worse, before JBoss 4.0.2 there was a flat classloader. Honestly, you wouldn't even think of making this stuff up...

So at last I've found a reason to love Weblogic - the error messages are useless, but at least it gives you reasonable control over class loading.