API Rest - OneToMany / ManyTone with JPA and Hibernate - spring

Question

I have the following relationship with this two entities
· Sport has Many SportTranslation
· SportTranslation belongsTo Sport
· Is Bidirectional
When I try to access from SportTranslation to Sport I recieve the following error.
java.lang.StackOverflowError: null
at java.util.AbstractCollection.toString(AbstractCollection.java:454) ~[na:1.8.0_191]
at org.hibernate.collection.internal.PersistentBag.toString(PersistentBag.java:510) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
The error is not clear and the tables are not empty.
· I have the classical following Spring MVC architecture
The controller
#RestController
#RequestMapping("/api/public/sports")
public class SportController implements ISportsController {
Logger logger = LoggerFactory.getLogger(SportController.class);
#Autowired
private SportsMethods sportMethods;
#GetMapping(value = "/")
#Override
public ResponseEntity<List<SportDTO>> getSports(Pageable pageable) {
logger.info("--- Retrieve name of class --- : " +this.getClass().getSimpleName() + " --- Method name --- : " + new Object(){}.getClass().getEnclosingMethod().getName());
List<SportDTO> sportsMethodsList = sportMethods.retreiveListSports(pageable);
logger.info("--- Final list ---" + sportsMethodsList);
return new ResponseEntity<List<SportDTO>>(sportsMethodsList,
(sportsMethodsList == null || sportsMethodsList.isEmpty()) ? HttpStatus.NO_CONTENT : HttpStatus.OK);
}
}
· Class Methods
#Component
public class SportsMethods {
#Autowired
private SportService sportService;
public List<SportDTO> retreiveListSports(Pageable pageable) {
List<SportDTO> sportList = sportService.retreiveListSports();
return sportList;
}
}
· The service
#Component
public class SportService implements ISportService {
Logger logger = LoggerFactory.getLogger(SportService.class);
#Autowired
private SportRepository sportRepository;
#Autowired
private SportAdapter sportAdapter;
#Override
public List<SportDTO> retreiveListSports() {
List<Sport> sportList = sportRepository.findAll();
logger.info("--- Retrieve List Of Sports---"+sportList);
List<SportDTO > sportListDTO = sportAdapter.convertListSport2ListSportDTO(sportList);
logger.info("--- Retrieve a List Of SportsDTO" +sportListDTO);
return sportListDTO;
}
}
· The two adapters (SportAdatper , SportTranslationAdapter)
· SportAdapter
#Component
public class SportAdapter {
Logger logger = LoggerFactory.getLogger(SportAdapter.class);
#Autowired
private SportTranslationAdapter sportTranslationAdapter;
public List<SportDTO> convertListSport2ListSportDTO(List<Sport> sportList) {
logger.info("--- Sport List adapter" + sportList);
List<SportDTO> sportDTOList = new ArrayList<SportDTO>();
for (Sport sport : sportList) {
SportDTO sportDTO = new SportDTO();
sportDTO.setId(sport.getId());
sportDTO.setClave(sport.getClave());
sportDTO.setSportTranslationDTO(sportTranslationAdapter.convertSportTranslation2SportTranslationDTO(sport.getSportTranslation()));
sportDTOList.add(sportDTO);
}
logger.info("--- Sport DTO List adapter" + sportDTOList);
return sportDTOList;
}
· SportTranslationAdapter
#Component
public class SportTranslationAdapter {
Logger logger = LoggerFactory.getLogger(SportTranslationAdapter.class);
public List<SportTranslationDTO> convertSportTranslation2SportTranslationDTO(List<SportTranslation> list) {
List<SportTranslationDTO> sportTranslationDTOList = new ArrayList<SportTranslationDTO>();
for (SportTranslation sportTranslation : list) {
SportTranslationDTO sportTranslationDTO = new SportTranslationDTO();
sportTranslationDTO.setSportId(sportTranslation.getSport().getId());
sportTranslationDTO.setName(sportTranslation.getName());
sportTranslationDTOList.add(sportTranslationDTO);
}
return sportTranslationDTOList;
}
}
· Entities Sport and SportTranslation
· Sport
#Entity
#Table(name = "sport")
public class Sport implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "sport_id")
private Long id;
#Column(name = "clave")
private String clave;
#OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
#JoinColumn(name = "sport_id")
private List<SportTranslation> sportTranslation;
·SportTranslation
#Entity
#Table(name = "sportstranslation")
public class SportTranslation implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "sportstranslation_id")
private long idSportTranslation;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "sport_id", nullable = true)
private Sport sport;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "language_id", nullable = true)
private Language languageId;
#Column(name = "name")
private String name;
· Language is working correctly ,but this is not the problem the problem is with Sport.
Could anyone helps to me?

Answer 1

I would suggest your entity association to updated as below:
#Entity
#Table(name = "sport")
public class Sport implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "sport_id")
private Long id;
#Column(name = "clave")
private String clave;
#OneToMany(mappedBy = "sport", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
private List<SportTranslation> sportTranslation;
#Entity
#Table(name = "sportstranslation")
public class SportTranslation implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "sportstranslation_id")
private long idSportTranslation;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "sport_id", nullable = true)
private Sport sport;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "language_id", nullable = true)
private Language languageId;
#Column(name = "name")
private String name;
Also, annotate your service method in which you are fetching data with #Transactional.