What is the structure of Modern Servlet Web Applications ?

A web application exists as a structured hierarchy.
The root of this hierarchy serves as a document root.

WEB-INF

• This directory contains all things related to the application that aren’t in the document root of the application.
• No file contained in the WEB-INF directory may be served directly to a client by the container.
• But, A servlet can access contents of WEB-INF using :
• ServletContext.gerResource()
• ServletContext.getResourceAsStream()

Contents under WEB-INF

• /WEB-INF/web.xml
  Deployment descriptor
  
• /WEB-INF/classes/*
  Directory for servlet and utility classes
  The classes in this directory are available to the application class loader.
  
• /WEB-INF/lib/*.jar
  contains JAR files (Java ARchive)
• JAR contain servlets, beans, and utility classes useful to the web application.
• The web application class loader
• can load class from any of these JAR files.
• loads classes from the WEB-INF/classes first, and then from JARs in the WEB-INF/lib directory