This section of the FAQ discusses common questions related to web application deployment.
Why does tomcat 5 create context configuration files?
Unlike tomcat 4.x, tomcat 5.x creates context configuration files for you in its conf/[Engine name]/[Host name] directory. This is part of the change in tomcat's configuration mechanism from version 4.x to make overall configuration more robust, flexible, and enterprise-friendly. Note, however, that this has changed the recommended deployment practices for web applications. These context configuration files are created by tomcat, but not removed by tomcat, because the user may have changed them or other files in the conf directory. The suggested practice for tomcat 5 is to place context configuration files in the META-INF/context.xml directory of your webapp, and use Tomcat's Manager webapp to deploy/undeploy your applications. More details can be found here: MARC Archive
Why does the memory usage increase when I redeploy a web application?
Because the Classloader (and the Class objects it loaded) cannot be recycled. They are stored in the permanent heap generation by the JVM, and when you redepoy a new class loader is created, which loads another copy of all these classes. This can cause OufOfMemoryErrors eventually.