Bobeirinha, mas me ajudou muito:

fonte: http://jaitechwriteups.blogspot.com/2006/07/know-how-log4j-tries-to-configure.html

Know how log4j tries to configure itself
Large number of applications use log4j for logging. Sometimes you may encounter cases where you sense that log4j is using some other configurations, other than the one that you expected it to use. You can debug the same by switching on the debug flag on log4j. Here's how you can do it:

Add -Dlog4j.debug to the command line. log4j will output info to std. out. telling you how it tries to configure itself.


Dah pra dar uma luz