WAR
Configuration
You can configure the WAR file of a Web project using the web.xml and web-j2ee-engine.xml deployment descriptors. They provide information the Web Container uses during deployment and at runtime. The web.xml provides the entries specified in J2EE, and the web-j2ee-engine.xml provides additional entries, specific to the J2EE Engine only. The DTD for this descriptor is web-j2ee-engine.dtd.
Configuration is extensively covered in J2EE Web Components Configuration.
Process Flow
Both deployment descriptors are automatically generated when you create a Web project. For more information, see Creating Web Projects. They are also automatically updated in the project each time changes are made in the project.
You can further edit the deployment descriptors using the multipage editor. For more information, see: