Why is Spring Data still using null references as return values?

Question

This is more a suggestion to improve than a question.

We all know about Tony Hoare's “billion dollar mistake” when inventing the zero link. Google Tips on the guava library wiki to avoid using null .

I really appreciate the Spring Data project, and we use Spring Data MongoDB in many projects. Is it likely that you will replace all possible null return reference values ​​with Optional<T> ? I think this will be a big improvement when using Spring Data repository abstraction.

I know that many interfaces will need to be changed, but the code changes are almost trivial, just return the return type to Optional.of(returnValue) .

Answer 1

Guava / JDK8 Optional<T> support has already been introduced with the RC1 Dijkstra exit train. Please check out spring -data-examples for java8 to find out how this works.

 interface CustomerRepository extends Repository<Customer, Long> { // CRUD method using Optional Optional<Customer> findOne(Long id); // Query method using Optional Optional<Customer> findByLastname(String lastname); } 

BTW: default methods are also supported there.

Answer 2

I think that one day Spring Data may refuse to support JDK versions older than JDK 8, so it’s quite simple to use JDK 8. However, since this will change the entire API, you will have to release a new major version, as well as upgrade paths, etc. (Changing the code would be trivial, but not the consequences for users of Spring data).

Answer 3

With the latest and greatest versions of Spring Data, CrudRepository now actually returns`