Did you know that Apple is shipping OS X with Java 1.4.2 set as the default JVM!!??
You have to manually set it use v1.5.0 in Java Preferences. How stupid is that!?
I just wasted the guts of two hours trying to figure out why my code wasn’t working before I realised that that was the problem.
UPDATE 25/4/06: Apple released a Software Update last week that set Java 1.5.0 as the default JVM.