JPA Repository Internals - How JpaRepository works internally?

Communication problem

Suppose we have a class named IpeopleRepository that extends JpaRepository.That class has no actual relation with neither SimpleJpaRepository nor SimpleJpaNoCountRepository, but still it has an access to it's native methods. My question is : There is obviously an assignment such as "if there is no implementation of JpaRepository ,then use SimpleJpaRepository as it's default implementation".How such configuration is made ? It seems like an autowire structure (in terms of Spring bean context). The image that describes the relation between repositories can be found under "communication problem" put above .