The lst line should read:
eturn (com.mypc.logging.Logger)Category.getInstance(name, factory);
The problem was resolved by renaming Logger class and also changing all references (painful process) to it.
Probably you have the Logger class in the Classpath twice?
Have you deployed it separately to your .ear ?
I've seen this when you've tried lots of things to get it working and haven't cleaned up properly. Try installing on a
clean JBoss install