The Web application is another subproject of the Model 2 Hello World application; it consists of a servlet, two JSPs, an HTML file, and a deployment descriptor. This section describes how to build a WAR file with a deployment descriptor. We also explain how to map servlets and JSPs to servlet elements in the deployment descriptor and how to map the servlet elements to URLs. In addition, this section breaks down the Web application project build file step by step, and shows how to use the build file to build and deploy the Web application.