Handling Lazy Initialization in Spring Boot with JPA - Unexpected NullPointerException
Hey everyone, I'm running into an issue that's driving me crazy... I'm working on a Spring Boot application (version 2.5.4) using JPA for database interactions, and I've run into a frustrating scenario with lazy loading. I have an `Order` entity that has a one-to-many relationship with `OrderItem`. When I try to access the `OrderItem` list after fetching the `Order` entity, I receive a `NullPointerException`. Here's the relevant part of my code: ```java @Entity public class Order { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @OneToMany(mappedBy = "order", fetch = FetchType.LAZY) private List<OrderItem> items; // Getters and setters } @Entity public class OrderItem { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @ManyToOne @JoinColumn(name = "order_id") private Order order; // Getters and setters } ``` In my service layer, I fetch the `Order` like this: ```java Order order = orderRepository.findById(orderId).orElseThrow(() -> new EntityNotFoundException("Order not found")); List<OrderItem> items = order.getItems(); // This line throws NullPointerException ``` I verified that the `Order` object is not null, but when I try to access `getItems()`, it seems to be `null`. I suspect that it might be an scenario related to the transaction scope, but I need to figure out how to resolve it. I've tried changing the fetch type to `EAGER`, but it still doesn't work properly in all cases. I also checked if the database actually has `OrderItem` entries for the given `Order`, and it does. What could cause this `NullPointerException` and how can I avoid it while keeping lazy loading for performance reasons? Hoping someone can shed some light on this.