Product.java

@Entity
@Table(name ="product")
public class Product {

    private Integer id;
    private String name;
    private List<ProductItem> productItems =new LinkedList<ProductItem>();

    public Product() {
    }

    @Id
    @GenericGenerator(name ="generator", strategy ="increment")
    @GeneratedValue(generator ="generator")
    @Column(name ="product_id", nullable =false)
    public Integer getId() {
        returnthis.id;
    }

    publicvoid setId(Integer id) {
        this.id = id;
    }

    @Column(name ="name")
    public String getName() {
        returnthis.name;
    }

    publicvoid setName(String name) {
        this.name = name;
    }

    /*
     * Here is the annotation to add in order to
     * Hibernate to automatically insert and update
     * ProducItems (if any)
     */
    @OneToMany(fetch = FetchType.LAZY, mappedBy ="pk.product", cascade = 
    {CascadeType.PERSIST, CascadeType.MERGE})
    @Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE, 
    org.hibernate.annotations.CascadeType.DELETE_ORPHAN})
    public List<ProductItem> getProductItems() {
        returnthis.productItems;
    }

    publicvoid setProductItems(List<ProductItem> productItems) {
        this.productItems = productItems;
    }
}