Unexpected NullPointerException with Spring Boot and JPA when Fetching Entity by ID
I'm writing unit tests and I've tried everything I can think of but Quick question that's been bugging me - I'm working with a `NullPointerException` when trying to fetch an entity by its ID using Spring Data JPA in my Spring Boot application. The behavior occurs intermittently, and I need to seem to pinpoint the cause. My entity looks like this: ```java @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String name; private String email; // getters and setters } ``` I have a repository interface defined as follows: ```java public interface UserRepository extends JpaRepository<User, Long> { } ``` And I'm trying to fetch a user in my service class: ```java @Service public class UserService { @Autowired private UserRepository userRepository; public User getUserById(Long id) { return userRepository.findById(id).orElseThrow(() -> new RuntimeException("User not found")); } } ``` When I call `getUserById()` with a valid `id`, it works fine most of the time, but in some cases, it throws a `NullPointerException` on the line where I'm returning the user. I have verified that the `id` being passed is valid and corresponds to an existing user in the database. I’ve double-checked my database connection and even tested the queries directly on the database. It seems like it could be a race condition or something similar, since the exception does not occur consistently. I'm using Spring Boot 2.5.3 with Hibernate 5.5.3, and my database is PostgreSQL 13. I have also added logging and see that the `id` is always present when the method is called. Any insights or suggestions on why this might be happening would be greatly appreciated! I'm working on a API that needs to handle this. Is there a better approach?