[java] petite problème avec JPA helps please

package testt;   

import javax.persistence.EntityManagerFactory;   
import javax.persistence.Persistence;   
import testt.exceptions.PreexistingEntityException;   

/**   
 *   
 * @author marwen   
 */   
public class Testt {   

    /**   
     * @param args the command line arguments   
     */   
    public static void main(String[] args) throws PreexistingEntityException, Exception {   
           
           
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("testtPU");   
        Personne p=new Personne(2);   
        p.setNom("marwen");   
        PersonneJpaController tjc=new PersonneJpaController(emf);   
          
            tjc.create(p);   
              
            System.out.println("succeed! l'objet est inséré");   
    }   
}   

/*   
 * To change this template, choose Tools | Templates   
 * and open the template in the editor.   
 */   
package testt;   

import java.io.Serializable;   
import javax.persistence.*;   
import javax.xml.bind.annotation.XmlRootElement;   

/**   
 *   
 * @author marwen   
 */   
@Entity   
@Table(name = "PERSONNE", catalog = "", schema = "ROOT")   
@XmlRootElement   
@NamedQueries({   
    @NamedQuery(name = "Personne.findAll", query = "SELECT p FROM Personne p"),   
    @NamedQuery(name = "Personne.findById", query = "SELECT p FROM Personne p WHERE p.id = :id"),   
    @NamedQuery(name = "Personne.findByNom", query = "SELECT p FROM Personne p WHERE p.nom = :nom")})   
public class Personne implements Serializable {   
    private static final long serialVersionUID = 1L;   
    @Id   
    @Basic(optional = false)   
    @Column(name = "ID", nullable = false)   
    private Integer id;   
    @Column(name = "NOM", length = 30)   
    private String nom;   

    public Personne() {   
    }   

    public Personne(Integer id) {   
        this.id = id;   
    }   

    public Integer getId() {   
        return id;   
    }   

    public void setId(Integer id) {   
        this.id = id;   
    }   

    public String getNom() {   
        return nom;   
    }   

    public void setNom(String nom) {   
        this.nom = nom;   
    }   

    @Override   
    public int hashCode() {   
        int hash = 0;   
        hash += (id != null ? id.hashCode() : 0);   
        return hash;   
    }   

    @Override   
    public boolean equals(Object object) {   
        // TODO: Warning - this method won't work in the case the id fields are not set   
        if (!(object instanceof Personne)) {   
            return false;   
        }   
        Personne other = (Personne) object;   
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {   
            return false;   
        }   
        return true;   
    }   

    @Override   
    public String toString() {   
        return "testt.Personne[ id=" + id + " ]";   
    }   
       
}

/*   
 * To change this template, choose Tools | Templates   
 * and open the template in the editor.   
 */   
package testt;   

import java.io.Serializable;   
import java.util.List;   
import javax.persistence.EntityManager;   
import javax.persistence.EntityManagerFactory;   
import javax.persistence.Query;   
import javax.persistence.EntityNotFoundException;   
import javax.persistence.criteria.CriteriaQuery;   
import javax.persistence.criteria.Root;   
import testt.exceptions.NonexistentEntityException;   
import testt.exceptions.PreexistingEntityException;   

/**   
 *   
 * @author marwen   
 */   
public class PersonneJpaController implements Serializable {   

    public PersonneJpaController(EntityManagerFactory emf) {   
        this.emf = emf;   
    }   
    private EntityManagerFactory emf = null;   

    public EntityManager getEntityManager() {   
        return emf.createEntityManager();   
    }   

    public void create(Personne personne) throws PreexistingEntityException, Exception {   
        EntityManager em = null;   
        try {   
            em = getEntityManager();   
            em.getTransaction().begin();   
            em.persist(personne);   
            em.getTransaction().commit();   
        } catch (Exception ex) {   
            if (findPersonne(personne.getId()) != null) {   
                throw new PreexistingEntityException("Personne " + personne + " already exists.", ex);   
            }   
            throw ex;   
        } finally {   
            if (em != null) {   
                em.close();   
            }   
        }   
    }   

    public void edit(Personne personne) throws NonexistentEntityException, Exception {   
        EntityManager em = null;   
        try {   
            em = getEntityManager();   
            em.getTransaction().begin();   
            personne = em.merge(personne);   
            em.getTransaction().commit();   
        } catch (Exception ex) {   
            String msg = ex.getLocalizedMessage();   
            if (msg == null || msg.length() == 0) {   
                Integer id = personne.getId();   
                if (findPersonne(id) == null) {   
                    throw new NonexistentEntityException("The personne with id " + id + " no longer exists.");   
                }   
            }   
            throw ex;   
        } finally {   
            if (em != null) {   
                em.close();   
            }   
        }   
    }   

    public void destroy(Integer id) throws NonexistentEntityException {   
        EntityManager em = null;   
        try {   
            em = getEntityManager();   
            em.getTransaction().begin();   
            Personne personne;   
            try {   
                personne = em.getReference(Personne.class, id);   
                personne.getId();   
            } catch (EntityNotFoundException enfe) {   
                throw new NonexistentEntityException("The personne with id " + id + " no longer exists.", enfe);   
            }   
            em.remove(personne);   
            em.getTransaction().commit();   
        } finally {   
            if (em != null) {   
                em.close();   
            }   
        }   
    }   

    public List<Personne> findPersonneEntities() {   
        return findPersonneEntities(true, -1, -1);   
    }   

    public List<Personne> findPersonneEntities(int maxResults, int firstResult) {   
        return findPersonneEntities(false, maxResults, firstResult);   
    }   

    private List<Personne> findPersonneEntities(boolean all, int maxResults, int firstResult) {   
        EntityManager em = getEntityManager();   
        try {   
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();   
            cq.select(cq.from(Personne.class));   
            Query q = em.createQuery(cq);   
            if (!all) {   
                q.setMaxResults(maxResults);   
                q.setFirstResult(firstResult);   
            }   
            return q.getResultList();   
        } finally {   
            em.close();   
        }   
    }   

    public Personne findPersonne(Integer id) {   
        EntityManager em = getEntityManager();   
        try {   
            return em.find(Personne.class, id);   
        } finally {   
            em.close();   
        }   
    }   

    public int getPersonneCount() {   
        EntityManager em = getEntityManager();   
        try {   
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();   
            Root<Personne> rt = cq.from(Personne.class);   
            cq.select(em.getCriteriaBuilder().count(rt));   
            Query q = em.createQuery(cq);   
            return ((Long) q.getSingleResult()).intValue();   
        } finally {   
            em.close();   
        }   
    }   
       
}

<?xml version="1.0" encoding="UTF-8"?>   
<persistence version="2.0" xmlns="http://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/index.html" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/index.html http://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/persistence_2_0.xsd">   
  <persistence-unit name="testtPU" transaction-type="RESOURCE_LOCAL">   
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>   
    <class>testt.Personne</class>   
    <properties>   
      <property name="javax.persistence.jdbc.url" value="jdbc:derby://localhost:1527/personne"/>   
      <property name="javax.persistence.jdbc.password" value="1234"/>   
      <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>   
      <property name="javax.persistence.jdbc.user" value="root"/>   
      <property name="eclipselink.ddl-generation" value="drop-and-create-tables"/>   
    </properties>   
  </persistence-unit>   
</persistence>