It depends what you want to do. If you just want to work with servlets and/or JSPs, then I recommend that you actually download one of the many available servers which implement version 2.2 or later of the servlet API. The official reference implementation is Tomcat, available from the Apache group at http://jakarta.apache.org/ . I like Resin, from http://www.caucho.com/ and many people find it both easier to install and configure and faster than Tomcat. There are lots more available, which can be found with a simple web search such as Jetty, JRun, Paperclips etc. I think that all of the listed servers are free to developers, although some may require licence payments for commercial deployment.