Help for Session ZK Login Security

                HttpSession ses=(HttpSession) Sessions.getCurrent().getNativeSession();
                Security.setSes(ses);
                Security.setAtt(pdb.getIduser());
                Executions.sendRedirect("Main.zul");

public class Security {
    private static HttpSession ses;

    public static HttpSession getSes() {
        return ses;
    }

    public static void setSes(HttpSession ses) {
        Security.ses = (HttpSession) ses;
    }
    
    public static void setAtt(String val){
        ses.setAttribute("ruser",val);
    }
    public static void logout(){
        ses.removeAttribute("ruser");
        ses.invalidate();
    }
}

       System.out.println(Security.getSes().getId());
       System.out.println(Security.getSes().getAttribute("ruser"));