mysql – How to use HttpSession in jsp?

I have an index.jsp in which I have an include of the header and the footer.
I created in a servlet a session in which I save an object and I want to be able to work with this session from the .jsp but it gives me an error of duplicity …

index.jsp

 <%  HttpSession sesion = request.getSession(true);
     if (sesion.getAttribute("sesion_usuario") == null) {
                System.out.println("no hay sesion"); %>

header.jsp


servlet

    User user = u.leerUser (email);
                HttpSession session = request.getSession ();
                sesion.setAttribute ("user_section", user);
                nextPage = "/index.jsp";

error
Error