In this demo, we will create a listener and then add, remove and delete attributes from the request object so that the listener methods are invoked.

Follow the below steps in order. You should have already configure apache tomcat with eclipse as mentioned in configuring-apache-tomcat-with-eclipse.

Create a new Dynamic Web project in eclipse as:

• go to File >New > Dynamic Web Project

All web applications in a Java EE server have their own unique context roots. A web application's context is reprecented by an implementation of the ServletContext interface. Each web application has only one servletContext and one ServletContext belongs to only one application. Servlets need to make use of the container interface to communicate with other components outside of their application or even within their application. 

A servlet can use a ServletContext object for various purposes, including:

RequestDispatcher mechanism used for forwarding to and including other resources. We will understand the basics of RequestDispatcher mechanism using a simple exercise.

Before proceeding, you need to configure your eclipse and tomcat. I am using eclipse Eclipse Java EE IDE for Web Developers version: Luna and Apache Tomcat version 8.0.18. Apache Tomcat version 8.0.18 support Servlet Spec 3.1, JSP Spec 2.3, EL Spec 3.0, WebSocket spec 1.1 and support java version 7 and above.