Hi all. using session tracking technique : HttpSession session = request.getSession( ); // inside a servlet session.setAttribute(" ", " "); // inside a JSP how to make the cookie a *persistent cookie* ? not disappear at the session end when closing the browser ? another thing please: As I know, if the client enabling or disabling the cookies inside his browser, I should not care, the container will take care. In my application, I have used the session tracking and I have enabled the cookiesand every thing fine, but when disabling them, a NullPointerException is thorwn because the cart object is not created). So, how to know of the client disabling the cookies ? and if so, what should I do ?