Java Servlet Programing Laungage

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 <servlet>
   <servlet-name>sessionBindingServlet</servlet-name>
   <servlet-class>r4r.servlet.sessionBindingServlet</servlet-class>
 </servlet>
	<servlet-mapping>
        <servlet-name>sessionBindingServlet</servlet-name>
        <url-pattern>/sessionBindingServlet</url-pattern>
    </servlet-mapping>
	 <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>

Index.jsp

<%-- 
    Document   : index.jsp
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
       <meta http-equiv="Content-Type"
	         content="text/html; charset=UTF-8">
       <title>r4r.co.in-servlet</title>
    </head>
    <body>
      <form>
       <h1>Access Servlet by servlet's Name!</h1>
       <a href="sessionBindingServlet">sessionBindingServlet</a>
      </form>
    </body>
</html>

Servlet Program

/*
 * Save as a sessionBindingServlet.java
 */
package r4r.servlet;
import java.io.*;
import java.text.*;
import java.util.Calendar;
import javax.servlet.*;
import javax.servlet.http.*;

/**
 *
 * @author R4R
 */
public class sessionBindingServlet extends HttpServlet {

 protected void processRequest
 (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
  response.setContentType("text/html;charset=UTF-8");
  PrintWriter out = response.getWriter();
  try {
/* TODO output your page here */
out.println("<html>");
out.println("<head>");
out.println("<title>" + getServletInfo() + "</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet sessionBindingServlet at " 
	          + request.getContextPath() + "</h1>");
out.println
 ("<form action=\"sessionBindingServlet\" method=\"POST\">");
out.println
 ("<input type=\"submit\" value=\"SessionBinding\"/>");
out.println("</form>");
out.println("</body>");
out.println("</html>");
  } finally {
out.close();
  }
 }

 @Override
 protected void doGet
 (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
  processRequest(request, response);
 }

 @Override
 protected void doPost
(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
  response.setContentType("text/html;charset=UTF-8");
  PrintWriter out = response.getWriter();
  try {
//get session if necessary then create a new session
HttpSession session = request.getSession();
// pass value in session attribute
session.setAttribute("sessionBinding",
	new SessionBindingListener(getServletContext(), out));
  } finally {
// free resource
out.flush();
out.close();
  }
 }

 @Override
 public String getServletInfo() {
  return "r4r.co.in-sessionBindingServlet";
 }
}
SessionBindingListener Program -

/*
 * Save as a SessionBindingListener.java
 */
class SessionBindingListener
	implements HttpSessionBindingListener {

 private ServletContext context;
 private PrintWriter out;
 //get custom data/time
 private DateFormat dateFormat =
	 new SimpleDateFormat("dd/MM/yyyy");
 String newDate = 
	 dateFormat.format(Calendar.getInstance().getTime());

 SessionBindingListener
	 (ServletContext servletContext, PrintWriter out) {
  this.context = servletContext;
  this.out = out;
 }

 @Override
 public void valueBound(HttpSessionBindingEvent event) {
  //Print massage on browser
  out.println("Session bound on [" 
	  + newDate + "] with <b>" + event.getName() + 
  "</b> to id : <I>" + event.getSession().getId() + "</I>");
  //Print massage on server console
  context.log("Session bound on [" 
	  + newDate + "] with <b>" + event.getName() + 
 "</b> to id : <I>" + event.getSession().getId() + "</I>");
 }

 @Override
 public void valueUnbound(HttpSessionBindingEvent event) {
  out.println("Session Unbound on [" 
	  + newDate + "] with <b>" + event.getName() +
 "</b> to id : <I>" + event.getSession().getId() + "</I>");
  context.log("Session Unbound on ["
  + newDate + "] with <b>" + event.getName() +
  "</b> to id : <I>" + event.getSession().getId() + "</I>");
 }
}