Session Rules from Servlet to JSP

Question

I'm getting a null pointer exception from the else statement in the JSP below when I check to see if a user has been authenticated by a servlet.
Are there any problems with the else statement to cause an exception?
<% /**Verify Authenticationt*/
HttpSession mysession = request.getSession();
String loginUrl = "/hr/servlet/SessionLoginServlet";
if (mysession==null)
response.sendRedirect(loginUrl);
else {  //below code causing null pointer exception
String loggedIn = (String) mysession.getAttribute("loggedIn");
if (!loggedIn.equals("true"))
response.sendRedirect(loginUrl);
%>
The Servlet's doPost:
public void doPost(HttpServletRequest request, HttpServletResponse
response)throws ServletException, IOException {
String userName = request.getParameter("userName");
String password = request.getParameter("password");
if (login(userName, password, response)) {
//send cookie to the browser
HttpSession session = request.getSession(true);
session.setAttribute("loggedIn", new String("true"));
response.sendRedirect("/hr/jsp/PAStart.jsp");
else {
sendLoginForm(response, true);
}

Answer 1

Unfortunately, no. You'll need to say:
if (loggedIn != null || !loggedIn.equals("true"))
It's how the equals() works for String objects. You need two objects to check equality.