Miguel,
if you're using
Tomcat, place your log4jconfig.xml file in WEB-INF/classes directory and log4j.jar in the lib directory. Taht will initialize Log4J.
If you want to use a special
Servlet,
this might help.
you web.xml should have
if you have an xml config file, use DOMConfigurator instead of PropertyConfigurator.
Hope this helps,
Regards,