Sun Java System Web Server 6.1 SP6 Programmer's Guide to Web Applications

Servlet by Extension of Servlet by Directory

This is not supported in Sun Java System Web Server 6.1. You can deploy a web application to respond to a directory, but all of the servlets must be in the WEB-INF/classes directory of the web application. You can no longer copy a servlet in the .class file into the document tree and have it run as a servlet or have all of the contents of a directory run as a servlet. The web application will treat only .class files as servlets.