title: Hibernate - Jboss Forge add a null element in my list ManyToMany
body: <p>I generate simple CRUD with Jboss forge. It's ok but when i get the list of my Entity (<code>postesPrejudices</code>) , a null element is added : </p>
  
  <p>My entity :</p>
  
  <pre><code>@ManyToMany
  @JoinTable(name = "COR_TYPEFICHE_REGRPRJ", 
          joinColumns = {@JoinColumn(name = "ID_TYPEFICHE", referencedColumnName = "ID")}, 
          inverseJoinColumns = @JoinColumn(name = "ID_REGRPRJ", referencedColumnName = "ID"))
  @OrderColumn(name = "ORDRE")
  private List&lt;RegroupementPostePrejudice&gt; postesPrejudices;
  </code></pre>
  
  <p>Here is my view, I use classic View with unit persist:</p>
  
  <pre><code>@Named
  @Stateful
  @ConversationScoped
  public class TypeFicheBean implements Serializable {
  ...
  
      @Inject
      private Conversation conversation;
  
      @PersistenceContext(unitName = "persistence-unit", type = PersistenceContextType.EXTENDED)
      private EntityManager entityManager;
  
      public void retrieve() {
  
          if (FacesContext.getCurrentInstance().isPostback()) {
              return;
          }
  
          if (this.conversation.isTransient()) {
              this.conversation.begin();
              this.conversation.setTimeout(1800000L);
          }
  
          if (this.id == null) {
              this.typeFiche = this.example;
          } else {
  
              this.typeFiche = findById(getId());
  
          }
      }
  
  public TypeFiche findById(Long id) {
          return this.entityManager.find(TypeFiche.class, id);
      }
  </code></pre>