Deploying a Servlet 3.0 or Servlet 3.1 application is a breeze. Thanks to the servlet annotation types, you can deploy a servlet/JSP application without the deployment descriptor. Having said that, the deployment descriptor is still needed in many circumstances where more refined configuration is required. When the deployment descriptor is present, it must be named web.xml and located under the WEB-INF directory. Java classes must reside in WEB-INF/classes and Java libraries in WEB-INF/lib. All application resources must then be packaged into a single war file. A war file is basically a zip file with .war extension.
This chapter discusses deployment and the deployment descriptor.