The findById() is available in CrudRepository while getOne() is available in JpaRepository. The findById() returns null if record does not exist while the getOne() will throw an exception called EntityNotFoundException.
Here are some Spring Data JPA Practice questions for you, I haven't provided the answer to these questions but you can find them by doing some research. You can post the correct answers to these spring Data JPA question in the comments and I will pick the right one to put it here with your name.
