implementing Lazy Loading in JPA When Using Spring Data JPA with Custom Queries
I'm trying to figure out I've been working on this all day and I'm working with a question with lazy loading in a Spring Data JPA application. When I try to access an entity with a lazy-loaded relationship, I'm getting a `org.hibernate.LazyInitializationException: could not initialize proxy - no Session` behavior. I've defined my entities with the appropriate `@OneToMany` and `@ManyToOne` relationships, and I'm using the following configuration for my entities: ```java @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String name; @OneToMany(mappedBy = "user", fetch = FetchType.LAZY) private List<Order> orders; } @Entity public class Order { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "user_id") private User user; } ``` I am currently trying to fetch a user along with their orders using a custom query defined in my repository: ```java @Repository public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT u FROM User u LEFT JOIN FETCH u.orders WHERE u.id = ?1") Optional<User> findByIdWithOrders(Long userId); } ``` When I call `findByIdWithOrders(id)`, the `orders` collection is initialized as expected. However, if I later try to access the `orders` property outside of the transaction context, I get the `LazyInitializationException`. I've tried using `@Transactional` at the service layer, but that seems to only work if I access the orders immediately after fetching the user. My service method looks like this: ```java @Service public class UserService { @Autowired private UserRepository userRepository; @Transactional(readOnly = true) public User getUserWithOrders(Long userId) { return userRepository.findByIdWithOrders(userId) .orElseThrow(() -> new EntityNotFoundException("User not found")); } } ``` Is there a best practice for handling lazy loading in this scenario? Should I be modifying my repository or the way I access the `orders` collection? I want to avoid loading all orders eagerly as it could lead to performance optimization with large datasets. I'm working on a application that needs to handle this. Thanks in advance! I'm open to any suggestions. This is part of a larger REST API I'm building.