I'm trying to use variable substitution for my log file names, using the webapp / context name. (My use case is not literally a shared configuration, but two webapps deployed using copies of the same war with different names...so they each have their own logback.xml, though they are identical). I'm using the example on http://logback.qos.ch/faq.html#sharedConfiguration as my basis, and while it is working, my webapp ends up creating two log files. First it creates one called application-name_IS_UNDEFINED.log with some of the first messages logged during startup, and then foo.log (where foo is the app name) with all subsequent messages. So it seems to me that the contextInitialized method of ServletContextListener isn't early enough, and that the default logback config is initializing earlier. This is using Tomcat 7, and Java 7. How can I either hook into the earlier initialization or replace it? Where does that initialization happen? Is that static code? Thanks, Eric