how to count number os sessions

following code will help to count number of session in a web application

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;


public class SessionCount implements HttpSessionListener{
private static int numberOfSessions;

/**
* @return the numberOfSessions
*/
public static int getNumberOfSessions() {
return numberOfSessions;
}

/**
* @param aNumberOfSessions the numberOfSessions to set
*/
public static void setNumberOfSessions(int aNumberOfSessions) {
numberOfSessions = aNumberOfSessions;
}

public void sessionCreated(HttpSessionEvent se) {
setNumberOfSessions(getNumberOfSessions() + 1);
}

public void sessionDestroyed(HttpSessionEvent se) {
setNumberOfSessions(getNumberOfSessions() - 1);
}

}