HttpSession if Statment

Why is if executed if the value is null?

System out Result = null

protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    HttpSession session = request.getSession(false);

    String wrong = "Falscher Benutzer oder Passwort";

    if (session != null) {
        String user = (String) session.getAttribute("user");
        session.setAttribute("user", user);
        RequestDispatcher rs = request.getRequestDispatcher("start.jsp");
        rs.forward(request, response);
        System.out.println(user);
    } else {
        request.setAttribute("Fehler", wrong);
        RequestDispatcher rs = request.getRequestDispatcher("login.jsp");
        rs.forward(request, response);
    }

Thank you