Servlets Java

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;
public class Binder extends HttpServlet {
  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException,
      IOException {
    resp.setContentType("text/html");
    PrintWriter out = resp.getWriter();
    HttpSession session = req.getSession(true);
    SessionObject o = new SessionObject(getServletContext());
    session.setAttribute("Binder.object", o);
    out.println("");
    out.println("");
    out.println("Session Binder");
    out.println("");
    out.println("");
    out.println("Object bound to session " + session.getId());
    out.println("");
    out.println("");
    out.flush();
  }
}
class SessionObject implements HttpSessionBindingListener {
  ServletContext context;
  public SessionObject(ServletContext context) {
    this.context = context;
  }
  public void valueBound(HttpSessionBindingEvent event) {
    context.log("" + (new java.util.Date()) + " Binding " + event.getName() + " to session "
        + event.getSession().getId());
  }
  public void valueUnbound(HttpSessionBindingEvent event) {
    context.log("" + (new java.util.Date()) + " Unbinding " + event.getName() + " from session "
        + event.getSession().getId());
  }
}