@ManyToMany - data is not stored in the database

To simplify, there are tables in my database:

Car (pk="id_car")

CarAddon (pk="id_car_fk,id_addon_fk", 
`FK_car_addon_addon` FOREIGN KEY (`id_addon_fk`) REFERENCES `addon` (`id_addon`)
`FK_car_addon_car` FOREIGN KEY (`id_car_fk`) REFERENCES `car` (`id_car`)

Addon (pk="id_addon")

Soon: I have cars, many cars can have many add-ons (e.g. ABS, etc.).
There are tables with cars, add-ons and one table, which is a logical relationship.

In general, objects work fine. I have no problem saving data when I want to save one object. I have no problem when I need FETCH data, i.e. Car-> getAddon ();

But, when I am going to continue the collection, nothing happens. No exceptions were thrown; there was no new data in the database.

//DBManager is a singleton to create an EntityManager
EntityManager em = DBManager.getManager().createEntityManager();

em.getTransaction().begin();
Addon addon1 = new Addon();
addon1.setName("czesc1");
em.persist(addon1);
Addon addon2 = new Addon();
addon2.setName("czesc2");
em.persist(addon2);

car.setAddonCollection(new ArrayList<Addon>());
car.getAddonCollection().add(addon1);
car.getAddonCollection().add(addon2);
em.persist(car);
em.getTransaction().commit();

In this case, the add-ons were stored in the Addon table, on the car table. There is no new data in the CarAddon table, although the object has good data (debbuger has an add-on collection).

em.persist(car) em.merge(), :

"SEVERE: Persistence error in /admin/AddAuction : java.lang.IllegalStateException: During synchronization a new object was found through a relationship that was not marked cascade PERSIST: model.entity.Car[ idCar=0 ]."

:

  @Entity
  @Table(name = "addon")
  @XmlRootElement
  @NamedQueries({...})
  public class Addon implements Serializable {
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      @Basic(optional = false)
      @NotNull
      @Column(name = "id_addon")
      private Integer idAddon;

      @Size(max = 100)
      @Column(name = "name")
      private String name;

      @JoinTable(name = "car_addon", 
          joinColumns = {
          @JoinColumn(name = "id_addon_fk", referencedColumnName = "id_addon")}, 
          inverseJoinColumns = {
          @JoinColumn(name = "id_car_fk", referencedColumnName = "id_car")})
      @ManyToMany
      private List<Car> carCollection;

      @XmlTransient
      public List<Car> getCarCollection() {
          return carCollection;
      }

      public void setCarCollection(List<Car> carCollection) {
          this.carCollection = carCollection;
      }
  }



@Entity
@Table(name = "car")
@XmlRootElement
@NamedQueries({...)
public class Car implements Serializable {

    @ManyToMany(mappedBy = "carCollection", fetch= FetchType.EAGER, cascade=CascadeType.ALL)
    private List<Addon> addonCollection;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @NotNull
    @Column(name = "id_car")
    private Integer idCar;

    @XmlTransient
    public List<Addon> getAddonCollection() {
        return addonCollection;
    }

    public void setAddonCollection(List<Addon> addonCollection) {
        this.addonCollection = addonCollection;
    }
}

?

ps1. :

cascade=CascadeType.ALL przy @ManyToMany private List<Car> carCollection

.

ps2. Netbeans 7, EclipseLink MySQL ( Hibernate - )