👀 Views: 2 💬 Answers: 1 📅 Created: 2025-06-08

spring jpa hibernate nullpointerexception Java

I'm attempting to set up I've encountered a strange issue with Quick question that's been bugging me - I'm working with a `NullPointerException` when trying to retrieve an entity using a custom repository in my Spring Data JPA project. I have a `User` entity and a custom repository interface that extends `JpaRepository`. Here's a snippet of the relevant code: ```java @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String username; private String email; // getters and setters } public interface UserRepository extends JpaRepository<User, Long> { Optional<User> findByUsername(String username); } ``` In my service, I call the custom repository method like this: ```java @Service public class UserService { @Autowired private UserRepository userRepository; public User getUserByUsername(String username) { return userRepository.findByUsername(username).orElseThrow(() -> new RuntimeException("User not found")); } } ``` However, when I invoke `getUserByUsername` in my controller, I'm seeing a `NullPointerException` with the message: ``` want to invoke "java.util.Optional.get()" because "userRepository.findByUsername(username)" is null. ``` I've checked the wiring of my `UserRepository`, and it correctly points to the database. The repository interface is implemented automatically by Spring, so I'm not sure why it would be null. I've tried using `@Autowired` explicitly on the repository and double-checked my application context configuration, but the scenario continues. Here's the Spring Boot version I'm using: 2.5.6, and my database is configured with H2 for testing. Any guidance on what might be causing this `NullPointerException` would be greatly appreciated! I'm working on a API that needs to handle this. Has anyone else encountered this? The project is a microservice built with Java. Could this be a known issue? Is there a simpler solution I'm overlooking?