Confusion about Spring Caching abstraction and Hibernate 2nd level cache

Question

I've been looking at Jhipster to learn how to setup caching correctly and there are a few things I don't understand.

This is the CacheConfig I have been using. It uses Ehcache with Hibernate 2nd level cache with use_query_cache=false.

When you annotate an Entity with @Cache:

@Entity
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class User extends AbstractAuditingEntity<Long> implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
    @SequenceGenerator(name = "sequenceGenerator")
    private Long id;

    @NotNull
    @Column(length = 50, unique = true, nullable = false)
    private String login;

And also in CacheConfig:

@Bean
public JCacheManagerCustomizer cacheManagerCustomizer() {
return cm -> {
      createCache(cm,io.github.jhipster.sample.repository.UserRepository.USERS_BY_LOGIN_CACHE);
      createCache(cm, io.github.jhipster.sample.domain.User.class.getName());
   };
}

You essentially cache User entity with both Spring Cache Abstraction and Hibernate 2nd level right? So now every time you access a user you will cache it twice.

I can confirm is this true with a listener and hibernate.properties.generate_statictics=true.

On top of that Jhipster also cache on @Repository level with:

@Cacheable(cacheNames = USERS_BY_LOGIN_CACHE)
Optional<User> findOneWithAuthoritiesByLogin(String login);

Overall I'm really confused on how and when to use Spring Cache Abstraction, Hibernate 2nd level cache. It seems like even with use_query_cache=false when you query findAll Hibernate will cache every entity that it returns.