From: In J2EE application, modules are packaged as EAR, JAR and WAR based on their functionality JAR: EJB modules which contain enterprise java beans (class files) and EJB deployment descriptor are packed as JAR files with.jar extenstion WAR: Web modules which contain Servlet class files, JSP Files, supporting files, GIF and HTML files are packaged as JAR file with.war (web archive) extension EAR: All above files (.jar and.war) are packaged as JAR file with.ear (enterprise archive) extension and deployed into Application Server. A WAR (Web Archive) is a module that gets loaded into a of a. A Java Application Server has two containers (runtime environments) - one is a Web container and the other is a EJB container. The Web container hosts Web applications based on JSP or the Servlets API - designed specifically for web request handling - so more of a request/response style of distributed computing. A Web container requires the Web module to be packaged as a WAR file - that is a special JAR file with a web. Vaidehi Serial Episode 1. xml file in the WEB-INF folder.