Почему не могу проинициализировать репозиторий?

Question

Vergil1718 @Vergil1718

Java
Spring

Почему не могу проинициализировать репозиторий?

при попытке ининциализировать репозиторий, у меня выходит ошибка
код контроллера MainController:

@Controller
public class MainController {

    public final FlagRepository flagRepository;

    @Autowired
    public MainController(FlagRepository flagRepository) {
        this.flagRepository = flagRepository;
    }

    @GetMapping("/")
    public String changeFlag(){
//        Flag flag = flagRepository.findById(1L);
//        flag.setFlag(0);
//        flagRepository.save(flag.getId());


        return "main";
    }

// ...
}

код интерфейса FlagRepository:

import com.blrmyfc.ComputerVision.domain.Flag;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface FlagRepository extends JpaRepository<Long, Flag> {
    Flag findById(Long l);
}

Класс сущность Flag:

import javax.persistence.*;

@Entity
@Table(name = "flag")
public class Flag {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private int flag;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public int getFlag() {
        return flag;
    }
    public void setFlag(int flag) {
        this.flag = flag;
    }
    public Flag() {
    }
    public Flag(int flag) {
        this.flag = flag;
    }
}

Лог ошибок:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mainController' defined in file [/home/blurmayface/Документы/ComputerVision/target/classes/com/blrmyfc/ComputerVision/controller/MainController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'flagRepository' defined in com.blrmyfc.ComputerVision.repo.FlagRepository defined in @EnableJpaRepositories declared on ComputerVisionApplication: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Long


Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'flagRepository' defined in com.blrmyfc.ComputerVision.repo.FlagRepository defined in @EnableJpaRepositories declared on ComputerVisionApplication: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Long

java.lang.IllegalArgumentException: Not a managed type: class java.lang.Long
	at org.hibernate.metamodel.internal.MetamodelImpl.managedType(MetamodelImpl.java:582) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.metamodel.internal.MetamodelImpl.managedType(MetamodelImpl.java:85) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]

Вообще не ясно в чем проблема :(