Java: What is Spring Data JPA?

1// Repository interface
2public interface UserRepository extends JpaRepository<User, Long> {
3    List<User> findByName(String name);
4    Optional<User> findByEmail(String email);
5    @Query("SELECT u FROM User u WHERE u.age > :age")
6    List<User> findOlderThan(@Param("age") int age);
7    @Query(value = "SELECT * FROM users WHERE active = true", nativeQuery = true)
8    List<User> findActiveUsers();
9}
10
11// Usage
12@Service
13public class UserService {
14    @Autowired
15    private UserRepository repo;
16    
17    public User createUser(User user) {
18        return repo.save(user);
19    }
20    public Optional<User> findById(Long id) {
21        return repo.findById(id);
22    }
23}