Java.lang.StackOverflowError: ноль для JPA saveAll

Я получаю эту ошибку при интеграции весенней загрузки с репозиторием JPA вот код

@CrossOrigin(origins = "http://localhost:4200")
@RestController
@RequestMapping("/api")
public class EmpController {

    @Autowired
    private CrudRepo crud;

    @Autowired
    private AddrCrudRepo addr;

    @Autowired
    private EntityManager entity;

    //@Autowired
    //private ModelMapper mapper;

private static int count = 0;


    @Bean
    public ModelMapper model() {
        return new ModelMapper();
    }

    //@Autowired
//  public EmpController(ModelMapper mapper) {
//      this.mapper = mapper;
//  }



    @RequestMapping(path = "/post-addr", method = RequestMethod.POST)
    public List<AddressModel> postAddr(@Valid @RequestBody List<AddressRequest> addr1){
    //  crud.findById(id)

        //AddressModel list = new AddressModel();

        EmployeeModel emp = new EmployeeModel();

        System.out.println("CALLING THE MAPPER "+addr1);
        List<AddressModel> addr_list = ObjectMapperUtils.mapAll(addr1, AddressModel.class);

        System.out.println("CALLED THE MAPPER "+addr_list);
        addr_list.forEach((a) -> {

            crud.findById(a.getEmpId()).ifPresent((b) -> {
                System.out.println(this.count++);
                a.setEmp_id(b);
                b.getAddress().add(a);

            });
        });


//      AddressModel addr_list = model().map(addr1, AddressModel.class);
//      
//      crud.findById(addr1.getEmp_id()).ifPresent((b) -> {
//          addr_list.setEmp_id(b);
//          
//      });`enter code here`
        System.out.println(addr_list.size());
        List<AddressModel> addr3 =  addr.saveAll(addr_list);
        System.out.println(addr3);
         return addr_list;

    }

получение ошибки в методе postAddr, когда он возвращает List<AddressModel>, а вот AddressModel

@Entity
@Table(name = "Emp_Address")
public class AddressModel  implements Serializable{

    @Column(name = "address_id")
    @Id
    private Integer address_id;

    @Column(name = "city")
    private String city;

    @Column(name = "states")
    private String states;

    @Transient
    private Integer empId;

    @ManyToOne
    @JoinColumn(name = "emp_id")
    private EmployeeModel emp_id;

    public AddressModel() {

    }

//getter and setter

и EmployeeModel

@Entity
@Table(name = "Employee")
public class EmployeeModel implements Serializable{

    @Column(name = "Emp_id")
    @Id
    private Integer emp_id;

    @Column(name = "Emp_Name")
    private String emp_name;

    @OneToMany(mappedBy = "emp_id")
    private Collection<AddressModel> address = new ArrayList<>();

    public EmployeeModel() {

    }

//getter and setters

поэтому, хотя saveAll выполняется правильно, но когда метод postAddr возвращает список, он выдает StackOverflow