无法刷新未管理的对象

我要刷新Eleve从数据库到Jtable的列表.在Jtable它的自我绑定到一个可观察到的list< Eleve >,所以任何添加/删除列表中会自动更新Jtable.

我的代码解释了它的自我:

EleveJpaController ejc = new EleveJpaController(emf);
java.util.Collection data = ejc.findEleveByNiveauClasseNomPrenom(niv, classe, nom, prenom);

for (Eleve entity : data) {
    entityManager.refresh(entity);
}

list.clear();
list.addAll(data);

List findEleveByNiveauClasseNomPrenom(a,v,x,n):

 public List findEleveByNiveauClasseNomPrenom(String niv,String classe,String nom, String prenom)
    {
        EntityManager em = getEntityManager();
        Query qr= em.createQuery("SELECT e FROM Eleve e WHERE e.niv.niv like '%"+niv+"%' and e.class1.libelle like '%"+classe+"%' and e.nom like '%"+nom+"%' and e.prenom like '%"+prenom+"%'");

       return qr.getResultList(); 
    }

正如你所看到的,它是一个很好的Eleve对象列表..那么为什么抛出这个异常呢？

[EL Info]: 2013-12-02 13:25:33.312--ServerSession(1903253526)--EclipseLink, version: Eclipse Persistence Services - 2.3.0.v20110604-r9504
[EL Info]: 2013-12-02 13:25:35.005--ServerSession(1903253526)--file:/C:/Users/marwen/Documents/NetBeansProjects/JocondeFinale/build/classes/_JocondeFinalePU login successful
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: Can not refresh not managed object: entities.Eleve[ idEleve=7 ].
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.refresh(EntityManagerImpl.java:943)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.refresh(EntityManagerImpl.java:849)
    at entities.GestionPaiement.niveauJcbbxItemStateChanged(GestionPaiement.java:736)
    at entities.GestionPaiement.access$2000(GestionPaiement.java:32)
    at entities.GestionPaiement$FormListener.itemStateChanged(GestionPaiement.java:607)
    at javax.swing.JComboBox.fireItemStateChanged(JComboBox.java:1225)
    at javax.swing.JComboBox.selectedItemChanged(JComboBox.java:1273)
    at javax.swing.JComboBox.contentsChanged(JComboBox.java:1329)
    at javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:118)
    at javax.swing.DefaultComboBoxModel.setSelectedItem(DefaultComboBoxModel.java:94)
    at javax.swing.JComboBox.setSelectedItem(JComboBox.java:578)
    at javax.swing.JComboBox.setSelectedIndex(JComboBox.java:624)
    at javax.swing.plaf.basic.BasicComboPopup$Handler.mouseReleased(BasicComboPopup.java:835)
    at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:290)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at javax.swing.plaf.basic.BasicComboPopup$1.processMouseEvent(BasicComboPopup.java:499)
    at java.awt.Component.processEvent(Component.java:6270)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2719)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
    at java.awt.EventQueue.access$200(EventQueue.java:103)
    at java.awt.EventQueue$3.run(EventQueue.java:694)
    at java.awt.EventQueue$3.run(EventQueue.java:692)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:708)
    at java.awt.EventQueue$4.run(EventQueue.java:706)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

干杯.