ProductItem.java

@Entity
@Table(name ="product_item")
@AssociationOverrides({
@AssociationOverride(name ="pk.item", joinColumns = @JoinColumn(name ="item_id")),
@AssociationOverride(name ="pk.product", joinColumns = @JoinColumn(name ="product_id"))
        })
public class ProductItem {

    private ProductItemPk pk =new ProductItemPk();

    @EmbeddedId
    private ProductItemPk getPk() {
        return pk;
    }

    privatevoid setPk(ProductItemPk pk) {
        this.pk = pk;
    }

    @Transient
    public Item getItem() {
        return getPk().getItem();
    }

    publicvoid setItem(Item item) {
        getPk().setItem(item);
    }

    @Transient
    public Product getProduct() {
        return getPk().getProduct();
    }

    publicvoid setProduct(Product product) {
        getPk().setProduct(product);
    }

    publicboolean equals(Object o) {
        if (this== o) returntrue;
        if (o ==null|| getClass() != o.getClass()) returnfalse;

        ProductItem that = (ProductItem) o;

        if (getPk() !=null?!getPk().equals(that.getPk()) : that.getPk() !=null) returnfalse;

        returntrue;
    }

    publicint hashCode() {
        return (getPk() !=null? getPk().hashCode() : 0);
    }
}