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Session Management in Java
Servlet Web Applications is a very interesting topic.
Session in Java
Servlet are managed through different ways, such as Cookies,
HttpSession
API, URL rewriting etc.
This is the third article in the series of Web Applications tutorial in Java, you might want to check out earlier two articles too.
Here is the LoginServlet that takes care of the login request.
package com.journaldev.servlet.session;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
* Servlet implementation class LoginServlet
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private final String userID = "Pankaj";
private final String password = "journaldev";
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// get request parameters for userID and password
String user = request.getParameter("user");
String pwd = request.getParameter("pwd");
if(userID.equals(user) && password.equals(pwd)){
Cookie loginCookie = new Cookie("user",user);
//setting cookie to expiry in 30 mins
loginCookie.setMaxAge(30*60);
response.addCookie(loginCookie);
response.sendRedirect("LoginSuccess.jsp");
}else{
RequestDispatcher rd = getServletContext().getRequestDispatcher("/login.html");
PrintWriter out= response.getWriter();
out.println("<font color=red>Either user name or password is wrong.</font>");
rd.include(request, response);
Notice the cookie that we are setting to the response and then forwarding it to LoginSuccess.jsp, this cookie will be used there to track the session. Also notice that cookie timeout is set to 30 minutes. Ideally there should be a complex logic to set the cookie value for session tracking so that it won’t collide with any other request.
Notice that if we try to access the JSP directly, it will forward us to the login page. When we will click on Logout button, we should make sure that cookie is removed from client browser.
There is no method to remove the cookie but we can set the maximum age to 0 so that it will be deleted from client browser immediately. When we run above application, we get response like below images.
When a JSP resource is used, container automatically creates a session for it, so we can’t check if session is null to make sure if user has come through login page, so we are using session attribute to validate request. CheckoutPage.jsp is another page and it’s code is given below.
<%@ page language="java" contentType="text/html; charset=US-ASCII"
pageEncoding="US-ASCII"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Login Success Page</title>
</head>
//allow access only if session exists
if(session.getAttribute("user") == null){
response.sendRedirect("login.html");
String userName = null;
String sessionID = null;
Cookie[] cookies = request.getCookies();
if(cookies !=null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("user")) userName = cookie.getValue();
<h3>Hi <%=userName %>, do the checkout.</h3>
<form action="LogoutServlet" method="post">
<input type="submit" value="Logout" >
</form>
</body>
</html>
Our LogoutServlet code is given below.
package com.journaldev.servlet.session;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
* Servlet implementation class LogoutServlet
@WebServlet("/LogoutServlet")
public class LogoutServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
Cookie[] cookies = request.getCookies();
if(cookies != null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("JSESSIONID")){
System.out.println("JSESSIONID="+cookie.getValue());
break;
//invalidate the session if exists
HttpSession session = request.getSession(false);
System.out.println("User="+session.getAttribute("user"));
if(session != null){
session.invalidate();
response.sendRedirect("login.html");
Notice that I am printing JSESSIONID cookie value in logs, you can check server log where it will be printing the same value as Session Id in LoginSuccess.jsp Below images shows the execution of our web application.
package com.journaldev.servlet.session;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
* Servlet implementation class LoginServlet
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private final String userID = "admin";
private final String password = "password";
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// get request parameters for userID and password
String user = request.getParameter("user");
String pwd = request.getParameter("pwd");
if(userID.equals(user) && password.equals(pwd)){
HttpSession session = request.getSession();
session.setAttribute("user", "Pankaj");
//setting session to expiry in 30 mins
session.setMaxInactiveInterval(30*60);
Cookie userName = new Cookie("user", user);
response.addCookie(userName);
//Get the encoded URL string
String encodedURL = response.encodeRedirectURL("LoginSuccess.jsp");
response.sendRedirect(encodedURL);
}else{
RequestDispatcher rd = getServletContext().getRequestDispatcher("/login.html");
PrintWriter out= response.getWriter();
out.println("<font color=red>Either user name or password is wrong.</font>");
rd.include(request, response);
<%@ page language="java" contentType="text/html; charset=US-ASCII"
pageEncoding="US-ASCII"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Login Success Page</title>
</head>
//allow access only if session exists
String user = null;
if(session.getAttribute("user") == null){
response.sendRedirect("login.html");
}else user = (String) session.getAttribute("user");
String userName = null;
String sessionID = null;
Cookie[] cookies = request.getCookies();
if(cookies !=null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("user")) userName = cookie.getValue();
if(cookie.getName().equals("JSESSIONID")) sessionID = cookie.getValue();
}else{
sessionID = session.getId();
<h3>Hi <%=userName %>, Login successful. Your Session ID=<%=sessionID %></h3>
User=<%=user %>
<!-- need to encode all the URLs where we want session information to be passed -->
<a href="<%=response.encodeURL("CheckoutPage.jsp") %>">Checkout Page</a>
<form action="<%=response.encodeURL("LogoutServlet") %>" method="post">
<input type="submit" value="Logout" >
</form>
</body>
</html>
<%@ page language="java" contentType="text/html; charset=US-ASCII"
pageEncoding="US-ASCII"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Login Success Page</title>
</head>
String userName = null;
//allow access only if session exists
if(session.getAttribute("user") == null){
response.sendRedirect("login.html");
}else userName = (String) session.getAttribute("user");
String sessionID = null;
Cookie[] cookies = request.getCookies();
if(cookies !=null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("user")) userName = cookie.getValue();
<h3>Hi <%=userName %>, do the checkout.</h3>
<form action="<%=response.encodeURL("LogoutServlet") %>" method="post">
<input type="submit" value="Logout" >
</form>
</body>
</html>
package com.journaldev.servlet.session;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
* Servlet implementation class LogoutServlet
@WebServlet("/LogoutServlet")
public class LogoutServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
Cookie[] cookies = request.getCookies();
if(cookies != null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("JSESSIONID")){
System.out.println("JSESSIONID="+cookie.getValue());
cookie.setMaxAge(0);
response.addCookie(cookie);
//invalidate the session if exists
HttpSession session = request.getSession(false);
System.out.println("User="+session.getAttribute("user"));
if(session != null){
session.invalidate();
//no encoding because we have invalidated the session
response.sendRedirect("login.html");
When we run this project keeping cookies disabled in the browser, below images shows the response pages, notice the jsessionid in URL of browser address bar. Also notice that on LoginSuccess page, user name is null because browser is not sending the cookie send in the last response. If cookies are not disabled, you won’t see jsessionid in the URL because Servlet Session API will use cookies in that case.
Thats all for session management in java servlets, we will look into Servlet Filters and Listeners and Cookies in future articles. Update: Check out next article in the series Servlet Filter.
if cookies are not disabled, you won’t see jsessionid in the URL because Servlet Session API will use cookies in that case. >> shouldn’t that be “if cookies are disabled, you won’t see jsessionid in the URL…”?
Hi Pankaj, Great article! Im working on session management for one my projects. I have one issue regarding the session for subsequent requests. The problem I am facing is I am creating the session in for endpoint in backend and setting a attribute in that session. But when I’m hitting the next subsequent endpoints I am not able to fetch the same session. I can see both session I’d and jsession id in the frontend. But somehow I’m not able to get it in the backend. Having said that the same implementation for login endpoint the session is successfully fetched for subsequent calls. Also when I’m hitting from postman I’m getting the session in the subsequent requests but when I try it from browser it won’t work. Any idea what could I be possibly missing here? Thanks.
Can you explain the difference between encodeURL and encodeRedirectURL. In my experiment, encodeRedirectURL in LoginServlet.java will append the session id into URL even if cookies are abled.
JournalDev
DigitalOcean Employee
•
September 4, 2021
if cookies are not disabled, you won’t see jsessionid in the URL because Servlet Session API will use cookies in that case. >> shouldn’t that be “if cookies are disabled, you won’t see jsessionid in the URL…”?
- abs
JournalDev
DigitalOcean Employee
•
May 24, 2020
Hi Pankaj, Great article! Im working on session management for one my projects. I have one issue regarding the session for subsequent requests. The problem I am facing is I am creating the session in for endpoint in backend and setting a attribute in that session. But when I’m hitting the next subsequent endpoints I am not able to fetch the same session. I can see both session I’d and jsession id in the frontend. But somehow I’m not able to get it in the backend. Having said that the same implementation for login endpoint the session is successfully fetched for subsequent calls. Also when I’m hitting from postman I’m getting the session in the subsequent requests but when I try it from browser it won’t work. Any idea what could I be possibly missing here? Thanks.
- Chaitresh Naik
JournalDev
DigitalOcean Employee
•
May 4, 2020
excellent article … As i m trying to understand what session is? And thanks for the use case.
- praneeth
JournalDev
DigitalOcean Employee
•
November 7, 2019
Really very good and useful article
- Ghulam Murtaza
JournalDev
DigitalOcean Employee
•
April 13, 2019
Thanks for this helpful material
- usman
JournalDev
DigitalOcean Employee
•
December 19, 2018
Hi, Pankaj. Your tutorials are very amazing! Can you tell me how you learn it, which books or documentation that you have read ? thank you so much!
- thuong pham
JournalDev
DigitalOcean Employee
•
June 2, 2018
Can you explain the difference between encodeURL and encodeRedirectURL. In my experiment, encodeRedirectURL in LoginServlet.java will append the session id into URL even if cookies are abled.
- suxin
JournalDev
DigitalOcean Employee
•
February 16, 2018
I am new to session management, but my question is, why we have used Cookie[] ?
- rajesh
JournalDev
DigitalOcean Employee
•
December 29, 2017
i was totally unaware of JSESSIONID, you should have explained it better. Thanks anyway. great job.
- Arun SIngh