Spring Boot - Issues with @Transactional and Lazy Loading in an Aggregate Root Structure
I'm confused about After trying multiple solutions online, I still can't figure this out... I'm relatively new to this, so bear with me. I'm encountering a frustrating issue with Spring Boot (version 2.5.4) where the `@Transactional` annotation doesn't seem to work as expected when dealing with lazy loading in an aggregate root structure. I've set up my entities with a one-to-many relationship, and I'm trying to fetch an aggregate root that has a collection of child entities. However, when I attempt to access the child entities outside of the transactional context, I get a `LazyInitializationException`. Here’s a simplified version of my code: ```java @Entity public class Parent { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @OneToMany(mappedBy = "parent", fetch = FetchType.LAZY) private List<Child> children; // Getters and setters } @Entity public class Child { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @ManyToOne @JoinColumn(name = "parent_id") private Parent parent; // Getters and setters } @Repository public interface ParentRepository extends JpaRepository<Parent, Long> { } @Service public class ParentService { @Autowired private ParentRepository parentRepository; @Transactional(readOnly = true) public Parent getParentWithChildren(Long id) { return parentRepository.findById(id).orElseThrow(() -> new EntityNotFoundException("Parent not found")); } } ``` When I call `getParentWithChildren` and then attempt to access `parent.getChildren()` outside of the transactional scope, it throws: ``` org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.example.Parent.children, no session or session was closed ``` I’ve tried adjusting the fetch type to `FetchType.EAGER` temporarily, which works but is not ideal due to the performance overhead with large datasets. I am aware that this is a common issue with lazy loading in JPA, but I thought that using `@Transactional` would manage the session properly. I've also looked into using `Hibernate.initialize()` within the service method, but that feels like a workaround rather than a proper solution. Does anyone have insights on how to properly manage this scenario or best practices to handle lazy loading with aggregate roots in Spring Boot? For context: I'm using Java on macOS. Has anyone else encountered this? My development environment is Ubuntu. What's the best practice here? Any ideas what could be causing this? Thanks in advance!