geting null, but expected randon UUID

geting null, but expected randon UUID
entity

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

  private UUID userId;
  private String firstName;
  private String lastName;
  private Gender gender;
  private Integer age;
  private String email;

   public enum Gender {
        MALE, FEMALE
    }
}  

service method

public int insertUser(User user) {
        return repository.insertUser(UUID.randomUUID(), user);
    }  

repository method

@Override
public int insertUser(UUID userId, User user) {
    database.put(userId, user);
    return 1;
}  

controller

@PostMapping()
public ResponseEntity<Integer> insertNewUser(@RequestBody User user) {
    int result = service.insertUser(user);
    if (result == 1) {
        return ResponseEntity.ok().build();
    }
    return ResponseEntity.badRequest().build();
}    

after insert entity and getting, it has userId null

>Solution :

Try:

@Override
public int insertUser(UUID userId, User user) {
    user.setUserId(userId);
    database.put(userId, user);
    return 1;
}