please i'm having this error if any one can explain it : while using an iterator in my methode public void createDemandeP() { if (demandep.getDateDebut().after(demandep.getDateFin())) { FacesContext .getCurrentInstance() .addMessage( null, new FacesMessage(FacesMessage.SEVERITY_WARN, "Attention aux dates", "la date de debut doit être avant la date de fin!")); } else if (demandep.getDateDebut().before(demandep.getDateFin())) { List<DemandeP> list = new ArrayList<DemandeP>(); list.addAll(chaletService.getChaletBylibelle(chaletChoisi).get(0) .getListDemandesP()); Iterator<DemandeP> it = list.iterator(); DemandeP d = it.next(); while (it.hasNext()) { if ((d.getDateDebut().compareTo(demandep.getDateDebut()) == 0) || (d.getDateFin().compareTo(demandep.getDateDebut()) == 0) || (d.getDateFin().compareTo(demandep.getDateFin()) == 0) || (d.getDateDebut().compareTo(demandep.getDateDebut()) == 0) || (d.getDateDebut().before(demandep.getDateDebut()) && d .getDateFin().after(demandep.getDateFin())) || (d.getDateDebut().before(demandep.getDateFin()) && d .getDateDebut().after(demandep.getDateDebut())) || (d.getDateFin().after(demandep.getDateDebut()) && d .getDateFin().before(demandep.getDateFin()))) { FacesContext.getCurrentInstance().getMessageList().clear(); FacesContext .getCurrentInstance() .addMessage( null, new FacesMessage( FacesMessage.SEVERITY_FATAL, "Periode Ou chalet indisponicle ", "Veillez choisir une autre marge de date !")); } } } else { demandep.setEtat("En traitement"); DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy"); Date date = new Date(); try { demandep.setDateDemande(dateFormat.parse(dateFormat .format(date))); } catch (ParseException e) { System.out.println("errooor date"); e.printStackTrace(); } nameUser = auth.getName(); // System.out.println(nameUser); adherent = utilisateurService.findAdherentByNom(nameUser).get(0); demandep.setUtilisateur(adherent); // System.out.println(chaletService.getChaletBylibelle(chaletChoisi).get(0).getLibelle()); demandep.setChalet(chaletService.getChaletBylibelle(chaletChoisi) .get(0)); demandep.setNouvelleDemande(true); demandePService.ajouterDemandeP(demandep); } } oct. 23, 2013 7:19:30 PM org.apache.catalina.core.StandardContext reload INFO: Le rechargement du contexte [/ONICLFINAL] a démarré oct. 23, 2013 7:19:30 PM org.apache.catalina.core.StandardWrapper unload INFO: Waiting for 1 instance(s) to be deallocated oct. 23, 2013 7:19:31 PM org.apache.catalina.core.StandardWrapper unload INFO: Waiting for 1 instance(s) to be deallocated oct. 23, 2013 7:19:32 PM org.apache.catalina.core.StandardWrapper unload INFO: Waiting for 1 instance(s) to be deallocated oct. 23, 2013 7:19:32 PM org.apache.catalina.core.ApplicationContext log INFO: Closing Spring root WebApplicationContext oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc SEVERE: The web application [/ONICLFINAL] registered the JDBC driver [com.mysql.jdbc.Driver] b but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/ONICLFINAL] appears to have started a thread named [MySQL Statement Cancellation Timer] but has failed to stop it. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SE VERE: The web application [/ONICLFINAL] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Hibernate Sessions registered for deferred close]) and a value of type [java.util.HashMap] (value [{org.hibernate.impl.SessionFactoryImpl@f6e256=[SessionImpl(PersistenceContext[entityKeys=[EntityKey[bo.DemandeP#1], EntityKey[bo.Utilisateur#3], EntityKey[bo.Chalet#1], EntityKey[bo.Role#2], EntityKey[bo.DemandeP#2]],collectionKeys=[CollectionKey[bo.Role.ListeUsers#2], CollectionKey[bo.Chalet.listPeriodes#1], CollectionKey[bo.Utilisateur.demandes#3], CollectionKey[bo.Utilisateur.demandesP#3], CollectionKey[bo.Chalet.listDemandesP#1]]];ActionQueue[insertions=[] updates=[] deletions=[] collectionCreations=[] collectionRemovals=[] collectionUpdates=[]])]}]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Request attributes]) and a value of type [org.springframework.web.context.request.ServletRequestAttributes] (value [org.apache.catalina.connector.RequestFacade@17f3488]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@51f78b]) and a value of type [org.springframework.security.core.context.SecurityContextImpl] (value [org.springframework.security.core.context.SecurityContextImpl@8e463c8b: Authentication: org.springframework.security.authentication.UsernamePasswordAuthenticationToken@8e463c8b: Principal: org.springframework.security.core.userdetails.User@311aa119: Username: maatouf; Password: [PROTECTED]; Enabled: true; AccountNonExpired: true; credentialsNonExpired: true; AccountNonLocked: true; Granted Authorities: ROLE_ADHER; Credentials: [PROTECTED]; Authenticated: true; Details: org.springframework.security.web.authentication.WebAuthenticationDetails@ffff4c9c: RemoteIpAddress: 0:0:0:0:0:0:0:1; SessionId: 14CD5D4E8E0E3AEB0367AB7115038FED; Granted Authorities: ROLE_ADHER]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@152e9b7]) and a value of type [net.sf.cglib.proxy.Callback[]] (value [[Lnet.sf.cglib.proxy.Callback;@6e1f4c]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [javax.faces.context.FacesContext$1] (value [javax.faces.context.FacesContext$1@9ecc6d]) and a value of type [com.sun.faces.context.FacesContextImpl] (value [com.sun.faces.context.FacesContextImpl@1c8bbed]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@1a9e75f]) and a value of type [com.sun.faces.context.FacesContextImpl] (value [com.sun.faces.context.FacesContextImpl@1c8bbed]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Locale context]) and a value of type [org.springframework.context.i18n.SimpleLocaleContext] (value [fr_FR]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:32 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/ONICLFINAL] created a ThreadLocal with key of type [com.sun.faces.application.ApplicationAssociate$1] (value [com.sun.faces.application.ApplicationAssociate$1@195266b]) and a value of type [com.sun.faces.application.ApplicationAssociate] (value [com.sun.faces.application.ApplicationAssociate@10d595c]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. oct. 23, 2013 7:19:33 PM org.apache.catalina.loader.WebappClassLoader validateJarFile INFO: validateJarFile(D:\newWorkSpace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\ONICLF INAL\WEB-INF\lib\servlet-api-2.5.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class oct. 23, 2013 7:19:33 PM org.apache.catalina.core.ApplicationContext log