Hibernate JPA IdentifierGenerationException: null id generated for class with @embeddedid

Question

I am having trouble mapping my database domain model to the program entities in one case where the entity is essentially a join table (a period) which combines two other ent

Answer 1

I was able to create the following mapping for my case (scala code) and could totally throw away the @Embeddable class:

@Entity
@Table(name = "payment_order_item", schema = "pg")
@IdClass(classOf[PaymentOrderItem])
final class PaymentOrderItem extends Serializable{

  @Id
  @ManyToOne
  @JoinColumn(name = "order_item_id", referencedColumnName = "id")
  var orderItem: OrderItem = _

  @Id
  @ManyToOne
  @JoinColumn(name = "payment_id", referencedColumnName = "id")
  var payment: Payment = _
}

So the following should work for you then

@Entity
@Table(name = "period")
@IdClass(Period.class)
public class Period extends Serializable{

    @Id
    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "day_idday", referencedColumnName = "id", nullable = false)
    private Day day;

    @Id
    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "timeslot_idtimeslot", referencedColumnName = "id", nullable = false)
    private Timeslot timeslot;

    //constructors, getters, setters, hashcode, and equals
}