do you supply your own log4j jar with the web application you're deploying? If so, this might be the reason for JBoss no longer logging. I've got the same problem where I use a 3rd party API that subclasses the log4j LoggerFactory, and this seems to interfere with JBoss' version of log4j. The effect is the same as you describe, no more logging. So, if you can rip out the log4j from your web app, try that ... if not (like in my case), I don't know ... if you come across a solution, please post it, I'd be interested in it as well!
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