Spring Data JPA findOne() change to Optional how to use this?

Question

I\'m learning SpringBoot2.0 with Java8.

And I followed some blog-making tutorial example.

The tutorial source code is:

Answer 1

I always write a default method "findByIdOrError" in widely used CrudRepository repos/interfaces.

@Repository 
public interface RequestRepository extends CrudRepository {

    default Request findByIdOrError(Integer id) {
        return findById(id).orElseThrow(EntityNotFoundException::new);
    } 
}