OneToMany lazy initialization when needing collection data

what’s a workaround if I have a relation OneToMany and would like to access the collection that is lazy loaded? Currently I get LazyInitializationException having this:

Club entity:

@Entity
public class Club {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;

    @OneToMany(mappedBy = "club", cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
    @JsonBackReference
    private List<Player> players;

Player entity:

Is it a good idea to have two methods, where one fetches data without players and the second one that fetches also players?

    @Override
    List<Club> findAll();

    @Query("Select clubs from Club clubs left join fetch clubs.players")
    List<Club> getAllClubsWithPlayers();

What I’m thinking of is that it is a bad idea, because if I have a situation where I have for example 4 properties that are lazy loaded and I’d need at once 3 of them, I’d have to have a query like: getAllClubsWithPlayersAndSponsorsAndCoaches, so I’d have to have a lot of combinations of such queries.
I don’t want to use EAGER, so could you tell me if it’s a common way to do this if I need access to players from the Club sometimes which is undoable with the findAll() method that throws LazyInitializationException?

Don’t understand me wrong – I know where the LazyInitializationException comes from, but I just don’t know what’s the best way to get access to players if I sometimes need them when fetching clubs. Is my way of doing it correct?

>Solution :

There are 3 choices:

1. Access all the lazy fields inside a @Transactional method. You don’t show your code, but there’s usually a Service Facade layer which is responsible for being @Transactional. It invokes Repositories.
2. Write a query that fetches all the required data. Then you’d have to create a method specifically to fetch all the lazy fields required for that logic.
3. Use OpenSessionInViewFilter or OpenSessionInViewInterceptor so that Session/EntityManager are started before the execution even reaches the Controller. The Session then would be closed by the same high-level layer at the end of the request processing.