Web Server web applications include two deployment descriptor files:
A Java EE standard file (web.xml) described in the Java Servlet 2.5 specification. You can find the specification at: http://java.sun.com/products/servlet/download.html.
The easiest way to create the web.xml and sun-web.xml files is to deploy a web application using Sun Java Studio Enterprise 8.1. For sample web.xml and sun-web.xml files, see Sample Web Application XML Files