java - Second request onwards did not work -

im doing java web project using sessions , filters. in code second request onwards requests did not work. can tell me why?

here code filterrequest.java code

public void init(filterconfig filterconfig) throws servletexception {         this.filterconfig = filterconfig;     }     public void dofilter(servletrequest req, servletresponse resp, filterchain chain) throws servletexception, ioexception {       try{           httpservletrequest request = (httpservletrequest) req;           httpservletresponse response = (httpservletresponse) resp;           //system.out.println("inside filter.............."  );           httpsession session = request.getsession(true);           user u = null;           if(session.getattribute("loggeduser")!=null){               u = (user) session.getattribute("loggeduser");           }                  if (u!= null || session.getattribute("loggeduser")!=null)           {               //system.out.println("user exits.." + u.getuname() );               chain.dofilter(req, resp);                     }else{                             //system.out.println("user not exits..");               string message = "please login!";                            request.setattribute("loginmsg", message);               response.sendredirect(request.getcontextpath() + "/login2.jsp?loginmsg=");                   //response.sendredirect("login2.jsp"); // infine loop occures           }       }catch(exception e){           e.printstacktrace();       }     }