Thanks very much Darran, I just needed to be sure ! I had to replace log.trace for log.debug, than I ran without problems on 4.0.5. But it was version Beta... I didn't try with the new version and I saw that the new one has much more classes !!! The ideal would be to have an updated version of log4j-boot.jar for JBoss 4.0.5... supporting the Logger.trace method.... Anyway, thanks very much !!! I'll have a look and check what's the best option for me !!! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4207047#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...