"Not an entity: class com.example.serverside.models.baseEntity.BaseEntity; nested exception is-CodePudding

I'm learning java spring boot which is generic pattern. now i found an error i've been looking for but couldn't find a crux of the problem.

when I do a GET in postman , it shows error 500 :

"Not an entity: class com.example.serverside.models.baseEntity.BaseEntity; nested exception is java.lang.IllegalArgumentException: Not an entity: class com.example.serverside.models.baseEntity.BaseEntity",

I've checked it a few times and have looked at similar questions but can't find an answer.

Here's my code on BaseEntity, GenericRepository, RegionService and RegionController.

Model BaseEntity `

package com.example.serverside.models.baseEntity;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
@MappedSuperclass
public class BaseEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

}

Model Region

package com.example.serverside.models;

import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import com.example.serverside.models.baseEntity.BaseEntity;
import com.fasterxml.jackson.annotation.JsonProperty;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;





@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name="region")
public class Region extends BaseEntity {

    
    @Column( nullable = false)
    private String name;

    @JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
    @OneToMany(mappedBy = "region", cascade = CascadeType.ALL)
    private List<Country> countries;


}

GenericRepository

package com.example.serverside.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.example.serverside.models.baseEntity.BaseEntity;

@Repository
public interface GenericRepository<T extends BaseEntity> extends JpaRepository<T,Long> {
    
}

RegionService

package com.example.serverside.services;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.example.serverside.models.Region;
import com.example.serverside.repository.GenericRepository;




@Service
public class RegionService {


    private GenericRepository<Region> regionRepository;

    @Autowired
    public RegionService(GenericRepository<Region> regionRepository) {
        this.regionRepository = regionRepository;
    }
    
    // findAll
    public List<Region> findAll(){
        return regionRepository.findAll();
    }

}

RegionController

package com.example.serverside.controllers;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.example.serverside.models.Region;
import com.example.serverside.services.RegionService;

import lombok.AllArgsConstructor;


@RestController
@RequestMapping("/api/v1/region")
public class RegionController{


    private RegionService regionService;

    @Autowired
    public RegionController(RegionService regionService) {
        this.regionService = regionService;
    }

    @GetMapping
    public ResponseEntity<List<Region>> findAll() {
        return new ResponseEntity(regionService.findAll(), HttpStatus.OK);
    }

}

I hope to find the crux of my problem, and how to solve it

CodePudding user response：

public interface GenericRepository<T extends BaseEntity> extends JpaRepository<T,Long>

what is the purpose of creating a generic repository? BaseEntity is only a model which is extended by the real entities like Region. See that it has no @Entity annotation.

So, if you are storing region in database define the repository for Region.

public interface RegionRepository extends JpaRepository<Region, Long>