The Web Application Package
So far, we've talked about servlets as distinct objects. In what we've seen, the only thing binding them together is the notion of a shared HttpSession object. As you might guess, it is desirable to package servlets (and other Web resources) into a single package. We might want to do this so that we can host multiple applications on a single WebLogic Server, update a group of resources wholesale, or easily refer to a group of multiple resources under a single name.
About Web Applications
As of the servlet specification Version 2.2, a new feature was added to J2EE: the Web Application. A Web application is a collection of servlets, HTML pages, classes, and other resources that can be bundled and run on multiple containers ...