@Query(value=[SQL query with several joins],nativeQuery=true)
List<Media> mySQLQuery()

interface MyRepo implements<Media, Long>....

  myRepo.findAll() will return a List of Media objects.

public interface CustomQuery {
    public List<Integer>myCustomQuery(int id)
}

@Component
public class MediaRepositoryImpl implements CustomQuery {
    @PersistenceContext
    EntityManager manager;

    public List<Integer>myCustomQuery(int id){
        Query q = manager.createNativeQuery(SQL_QUERY_GOES_HERE);
        List<Integer> ids = new ArratList<Integer>();

        @SuppressWarnings("unchecked")
        List<Integer> result  = q.getResultList();
        for(Integer o : result){
            //process the results and add them to the list
        }
        return list;
    }
}