Quick Recap of J2EE

As can be seen here, a request for getting a jsp first reaches a web-server (e.g. apache). Apache checks up its virtualhost for the specified URL, identifies the document root, picks up the JSP, and then Apache then hands over the request via module mod_jk to Tomcat, whose job it is to do the following 

One can even look upon the processing as follows (taken from Wikipedia)

If one is looking at things from the J2EE model, one typically works with a MVC relationship between classes - the relationship works as follows (ill put up a picture on this soon).