JPA IdClass example

@Entity
public class Employee {
 @Id long empId;
 String empName;
 ...
}

public class DependentId {
 String name; // matches name of @Id attribute
 long emp; // matches name of @Id attribute and type of Employee PK
}

@Entity
@IdClass(DependentId.class)
public class Dependent {
 @Id String name;
// id attribute mapped by join column default
 @Id @ManyToOne Employee emp; ...
}