if (genderRepository.findOneByNome(gender.getName()) != null) {
                throw new RuntimeException("Name repeated");
        }
  return new ResponseEntity<>(genderService.save(gender), HttpStatus.CREATED);

@NoRepositoryBean
public interface CustomRepo<T, ID extends Serializable> extends GenericService<T, ID> {

    @Query("SELECT NEW #{#entityName} (t.id,t.name) FROM #{#entityName} as t ORDER BY t.name ASC")
    public List<T> findAll();

    @Query("SELECT NEW #{#entityName} (t.id,t.name) FROM #{#entityName} as t ORDER BY t.name ASC")
    public Page<T> pageAll();

    public T findOneByName(String nome);
}

public interface GenericService<T, I extends Serializable> {

    List<T> findAll();
    T getById(Long id);
    T create(T entity);
    T update(T entity);
    void deleteById(Long id);
}

@Repository
public interface GenderRepository extends CustomRepo<GenderEntity, Long> {

    @Query("Select m FROM GenderEntity g JOIN g.manga m where g.id=:id ORDER BY m.name ASC ")
    public Page<GenderEntity> findMangaById(@Param("id") Long id, Pageable page);
}

@Repository
public interface GroupRepository extends GenericService<GroupEntity, Long>{

    public Page<GroupEntity> findMangaByIdAutor(@Param("id")Long id, Pageable pageable);

    @Query(value="SELECT g FROM GroupEntity g where g.name LIKE :name%")
    public Page<GroupEntity> findByLetter(@Param("name") String name, Pageable pageable);
}

@Repository
public interface AuthorRepository extends GenericService<AuthorEntity, Long> {

    @Query("SELECT NEW AuthorEntity(id,name) FROM AuthorEntity a where a.name like :letra%")
    public Page<AuthorEntity> pageAllByLetter(@Param("letra") String name, Pageable pageable);

    @Query("Select m FROM AuthorEntity a JOIN a.manga m where a.id=:id ORDER BY m.name ASC")
    public Page<AuthorEntity> findMangaById(@Param("id") Long id, Pageable page);
}

@Service
public class AuthorService implements AutorRepository{
    //Custom impl
}

@Service
public class GenderService implements GenderRepository{
    //Custom impl
}

@Service
public class GrupoService implements GruposRepository {
    //Custom Impl
}