spring jpa add field to many to many table

1@Entity
2public class Employer {
3
4    @Id
5    @GeneratedValue(strategy = GenerationType.IDENTITY)
6    private int id;
7
8    @OneToMany(mappedBy = "employer")
9    private List<EmployerDeliveryAgent> deliveryAgentAssoc;
10
11    // other properties and getters and setters
12}
13
14@Entity
15public class DeliveryAgent {
16
17    @Id
18    @GeneratedValue(strategy = GenerationType.IDENTITY)
19    private int id;
20
21    @OneToMany(mappedBy = "deliveryAgent")
22    private List<EmployerDeliveryAgent> employerAssoc;
23
24    // other properties and getters and setters
25}
26
27@Entity
28@Table(name = "employer_delivery_agent")
29@IdClass(EmployerDeliveryAgentId.class)
30public class EmployerDeliveryAgent {
31
32    @Id
33    @ManyToOne
34    @JoinColumn(name = "employer_id", referencedColumnName = "id")
35    private Employer employer;
36
37    @Id
38    @ManyToOne
39    @JoinColumn(name = "delivery_agent_id", referencedColumnName = "id")
40    private DeliveryAgent deliveryAgent;
41
42    @Column(name = "is_project_lead")
43    private boolean isProjectLead;
44}
45
46public class EmployerDeliveryAgentId implements Serializable {
47
48    private int employer;
49    private int deliveryAgent;
50
51    // getters/setters and most importantly equals() and hashCode()
52}