Here’s a simple “HttpSessionListener” example to keep track the total number of active sessions in a web application. If you want to keep monitor your session’s create and remove behavior, then consider this listener.

Java Source

package com.mkyong;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
public class SessionCounterListener implements HttpSessionListener {
  private static int totalActiveSessions;
  public static int getTotalActiveSession(){
 return totalActiveSessions;
  public void sessionCreated(HttpSessionEvent arg0) {
 System.out.println("sessionCreated - add one session into counter");
  public void sessionDestroyed(HttpSessionEvent arg0) {
 System.out.println("sessionDestroyed - deduct one session from counter");