Explicit use of EntityManager with Spring Data repositories

When do I need to explicitly resort to EntityManager methods(I'm particularly interested in clear(), close(), flush(), detach()) inside my Service methods that additionally work with Spring Data repos?

I'm mostly interested in a general insight into the subject. Let's say in one application I found this:

    for ( MyEntity myEntity: entities) {
        ...some logic here
        mySpringDataRepo.save ( myEntity );
    }
    entityManager.flush ();
    entityManager.clear ();

I found such use of EntityManager justifiable since the memory can be overloaded with the entities. However, in another code snippet:

    mySpringDataRepository.save(entity);
    entityManager.detach(entity);

Is it necessary to explicitly detach the entity? Doesn't Spring Data handle it by itself?

I also found this post: http://ift.tt/1H2nLgy

which confused me even more.

As for the close() method I believe there's no need to call it in the EE environment. Am I correct?

PS: my configurations are very mainstream: JpaTransactionManager/LocalContainerEntityManagerFactoryBean