A question about authentication

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class LoginHandler extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
// Get the user's name and password
String name = req.getParameter("name");
String passwd = req.getParameter("passwd");
// Check the name and password for validity
if (!allowUser(name, passwd)) {
out.println("<HTML><HEAD><TITLE>Access Denied</TITLE></HEAD>");
out.println("<BODY>Your login and password are invalid.<BR>");
out.println("You may want to <A HREF=\"/login.html\">try again</A>");
out.println("</BODY></HTML>");
}
else {
// Valid login. Make a note in the session object.
HttpSession session = req.getSession(true);
session.putValue("logon.isDone", name);
// just a marker object
// Try redirecting the client to the page
//he first tried to access
<font color=red> try {
String target = (String) session.getValue("login.target");
if (target != null)
res.sendRedirect(target);
return;
}
catch (Exception ignored) { }</font>
// Couldn't redirect to the target.
//Redirect to the site's home page.
res.sendRedirect(req.getScheme() + "://" +
req.getServerName() + ":" + req.getServerPort());
}
}
protected boolean allowUser(String user, String passwd) {
return true; // trust everyone
}
}
Hi, I have a question about the above code. A person that tries to log in for the first time will have "taget" to be null. So, for a first timer, "target" will always be null, and there is no way to get around it to get a valid link?
Can someone please explain this to me?
Thanks!

you have to pass target value in parameter to servlet ,
based on that parameter get string and then send redirect.

This servlet is called by a HTML page that has only two parameters, name and passwd. So...