Since the SERVICE_USER table is not a pure join table, but has additional functional fields (blocked), you must map it as an entity, and decompose the many to many association between User and Service into two OneToMany associations : One User has many UserServices, and one Service has many UserServices.
You haven’t shown us the most important part : the mapping and initialization of the relationships between your entities (i.e. the part you have problems with). So I’ll show you how it should look like.
If you make the relationships bidirectional, you should thus have
class User {
@OneToMany(mappedBy = "user")
private Set<UserService> userServices = new HashSet<UserService>();
}
class UserService {
@ManyToOne
@JoinColumn(name = "user_id")
private User user;
@ManyToOne
@JoinColumn(name = "service_code")
private Service service;
@Column(name = "blocked")
private boolean blocked;
}
class Service {
@OneToMany(mappedBy = "service")
private Set<UserService> userServices = new HashSet<UserService>();
}
If you don’t put any cascade on your relationships, then you must persist/save all the entities. Although only the owning side of the relationship (here, the UserService side) must be initialized, it’s also a good practice to make sure both sides are in coherence.
User user = new User();
Service service = new Service();
UserService userService = new UserService();
user.addUserService(userService);
userService.setUser(user);
service.addUserService(userService);
userService.setService(service);
session.save(user);
session.save(service);
session.save(userService);