From http://logging.apache.org/log4j/1.2/faq.html#3.6
Is there a way to get log4j to
automatically reload a configuration
file if it changes?Yes. Both the DOMConfigurator and the
PropertyConfigurator support automatic
reloading through the
configureAndWatch method. See the API documentation for more
details.Because the configureAndWatch launches
a separate wathdog thread, and because
there is no way to stop this thread in
log4j 1.2, the configureAndWatch
method is unsafe for use in J2EE
envrironments where applications are
recycled.
Said that, I’ve successfully used PropertyConfigurator#configureAndWatch method in a Java EE environment (Sun One Web Server, not Tomcat).