Encountered a frustrating problem in our application today which came down to an ArrayIndexOutOfBounds exception being thrown. The exception's type was just about all that was logged which is fairly useless (but, oh dear legacy app, we still love you, mostly). I've redeployed the application with a change which logs the stack trace on exception handling (and immediately found the root cause of the problem) and wondered why no one else did this before. Do you generally log the stack trace and is there any reason you wouldn't do this?

Bonus points if you can explain (why, not how) the rationale behind having to jump hoops in java to get a string representation of a stack trace!