Question

i have 2 entities: User and Role
i have one class Userrole that will contain a composite key between user and role.

now Userrole will not contain userId and roleId.. but the object User and Role and it looks like this:

public class UserRole implements Serializable{
    User user;
    Role role;

can i put @Id on the User? like:

    @Id
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }

?

Answer 1

Using annotations, you need to define a proper class for your composite id, and annotate it as @Embeddable. (With XML, one can map the composite id without an explicit id class too.) Here is an example using an inner class as composite id, and another one, with a top-level id class.