A Web module represents a Web application. It is used to assemble servlets and JSP files, as well as static content such as HTML pages, into a single deployable unit. Web modules are stored in Web archive (WAR) files, which are standard Java archive files. The standard file extension for WAR files is .war. A Web module contains the following:
A Web module can be used as a stand-alone application, or it can be combined with other modules (other Web modules, EJB modules, or both) to create a J2EE application. A Web module is installed and run in a Web container.