The preceding discussion provides a brief introduction to servlets and JSP pages, but says nothing about how you actually use a server to run them. This section describes how to install Tomcat, a JSP-aware web server. Tomcat is part of the Jakarta Project, which like Apache is a development effort of the Apache Software Foundation.
As described earlier, servlets execute inside a container, which is an engine that communicates with or plugs into a web server to handle requests for pages that are produced by executing servlets. Some servlet containers can operate in standalone fashion, such that they function both as container and web server. That is how Tomcat works, so by installing it, you get a fully functioning server with servlet-processing capabilities. In fact, Tomcat is a reference implementation for both the servlet and JSP specifications, so it also acts as a JSP engine, providing JSP-to-servlet translation services. The servlet container part is named Catalina, and the JSP processor is named Jasper.
It’s possible to use the container part of Tomcat in conjunction with other web servers. For example, you can set up a cooperative arrangement between Apache and Tomcat under which Apache acts as a frontend that passes servlet and JSP requests through to Tomcat and handles other requests itself. You can find information about setting up Apache and Tomcat to work together this way on the Jakarta project web site.
To run a Tomcat server, you need three ...