Servlets Java

package com.ack.web.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class DestroyAServletSession extends HttpServlet {
public void doGet( HttpServletRequest req, HttpServletResponse res )
throws ServletException, IOException {
res.setContentType( "text/html" );
PrintWriter pw = res.getWriter();
pw.println( "" );
// get current session, and don't create one if it doesn't exist
HttpSession theSession = req.getSession( false );
// print out the session id
if( theSession != null ) {
pw.println( "
Session Id: " + theSession.getId() );
synchronized( theSession ) {
// invalidating a session destroys it
theSession.invalidate();
pw.println( "
Session destroyed" );
}
}
pw.println( "" );
pw.close();
}
}