What Is @Idclass

Specifies a composite primary key class that is mapped to multiple fields or properties of the entity. The names of the fields or properties in the primary key class and the primary key fields or properties of the entity must correspond and their types must be the same. Example: @IdClass(com.

What is the use of @EmbeddedId?

@EmbeddedId is used for composite primary key. i.e. more than one column behaves jointly as primary key. We need to create an entity as Embeddable and the Embeddable entity can be embedded in other entity to achieve composite primary key.

What is @MapsId?

The @MapsId annotation tells Hibernate to use the primary key value of the Book entity as the primary key value of the Manuscript entity.