👀 Views: 60 💬 Answers: 1 📅 Created: 2025-06-24

java spring jpa hibernate Java

I'm sure I'm missing something obvious here, but I'm working with a `NullPointerException` when trying to access a lazily-loaded collection in a JPA entity within a transactional service method. The behavior occurs intermittently, specifically when the entity is fetched from the database, and I try to access one of its lazy-loaded properties. Here’s a simplified version of my code: ```java @Entity public class User { @Id private Long id; private String name; @OneToMany(mappedBy = "user", fetch = FetchType.LAZY) private List<Order> orders; // Getters and setters } @Entity public class Order { @Id private Long id; private String product; @ManyToOne @JoinColumn(name = "user_id") private User user; } ``` In my service, I have the following method: ```java @Service public class UserService { @Autowired private UserRepository userRepository; @Transactional(readOnly = true) public User getUserWithOrders(Long userId) { User user = userRepository.findById(userId).orElseThrow(() -> new EntityNotFoundException("User not found")); // The following line occasionally throws NullPointerException List<Order> orders = user.getOrders(); return user; } } ``` This behavior seems to happen when the `User` entity is retrieved, but the `orders` list isn't initialized properly. I've tried changing the transaction propagation settings and also made sure that the repository method is indeed returning a `User` with associated `orders`. I am using Spring Data JPA with Hibernate 5.4 under Java 11. I added logging around the retrieval of the user and its orders, and the log shows that the user exists, but accessing `getOrders()` leads to a `NullPointerException`. Could this be due to the lazy loading not being initialized before the transaction ends? How can I ensure that the orders are loaded properly without running into this null pointer scenario? This is part of a larger API I'm building.