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

Put those guys

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

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

inside the PeriodId class and throw away those ints. I have done a mapping similar to yours this way and it works.