Illegal use of @Table in a subclass of a SINGLE_TABLE hierarchy

Question

I'm a newbie in Spring. I try to create a project with SOLID techniques but was faced with that error. Inheritance does not work in my application. Why inheritance does not work properly? Is inheritance allowed in Spring?

Text of Error:

    2021-06-23 23:54:08.928  INFO 12984 --- [  restartedMain] hrms.northwind.NorthwindApplication      : Starting NorthwindApplication using Java 15.0.2 on DESKTOP-87K40S0 with PID 12984 (C:\Users\90553\Desktop\Eclipse Projects\HRMS Project\target\classes started by 90553 in C:\Users\90553\Desktop\Eclipse Projects\HRMS Project)
2021-06-23 23:54:08.929  INFO 12984 --- [  restartedMain] hrms.northwind.NorthwindApplication      : No active profile set, falling back to default profiles: default
2021-06-23 23:54:08.978  INFO 12984 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2021-06-23 23:54:08.978  INFO 12984 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2021-06-23 23:54:09.465  INFO 12984 --- [  restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2021-06-23 23:54:09.512  INFO 12984 --- [  restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 40 ms. Found 2 JPA repository interfaces.
2021-06-23 23:54:10.040  INFO 12984 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-06-23 23:54:10.052  INFO 12984 --- [  restartedMain] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-06-23 23:54:10.052  INFO 12984 --- [  restartedMain] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.46]
2021-06-23 23:54:10.130  INFO 12984 --- [  restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-06-23 23:54:10.130  INFO 12984 --- [  restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1152 ms
2021-06-23 23:54:10.203  INFO 12984 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2021-06-23 23:54:10.367  INFO 12984 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2021-06-23 23:54:10.458  INFO 12984 --- [  restartedMain] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-06-23 23:54:10.502  INFO 12984 --- [  restartedMain] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.32.Final
2021-06-23 23:54:10.619  INFO 12984 --- [  restartedMain] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-06-23 23:54:10.721  INFO 12984 --- [  restartedMain] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.PostgreSQLDialect
2021-06-23 23:54:11.047  WARN 12984 --- [  restartedMain] org.hibernate.cfg.AnnotationBinder       : HHH000139: Illegal use of @Table in a subclass of a SINGLE_TABLE hierarchy: hrms.northwind.entities.concretes.Employer
2021-06-23 23:54:11.049  WARN 12984 --- [  restartedMain] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is java.lang.ClassCastException: class org.hibernate.mapping.SingleTableSubclass cannot be cast to class org.hibernate.mapping.RootClass (org.hibernate.mapping.SingleTableSubclass and org.hibernate.mapping.RootClass are in unnamed module of loader 'app')
2021-06-23 23:54:11.050  INFO 12984 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2021-06-23 23:54:11.053  INFO 12984 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
2021-06-23 23:54:11.057  INFO 12984 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-06-23 23:54:11.066  INFO 12984 --- [  restartedMain] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-06-23 23:54:11.084 ERROR 12984 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

Employer Class:

package hrms.northwind.entities.concretes;

import javax.persistence.Column;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

import javax.persistence.Table;

import lombok.Data;
@Entity(name="Employers")

@Table(name="Employers")
@Data
public class Employer extends Person {
    @Id
    @GeneratedValue
    @Column(name="employer_id")
    private int employerId;
    
    @Column(name="company_name")
    private String company_name;
    
    @Column(name="website")
    private String website;
    
    @Column(name="phone_number")
    private String phone_number;
    
    @Column(name="password")
    private String password;
    
    public Employer(int personId, String name, String surname, String email, int employerId, String company_name, String website,
            String phone_number, String password) {
        super(personId, name, surname, email);
        this.employerId = employerId;
        this.company_name = company_name;
        this.website = website;
        this.phone_number = phone_number;
        this.password = password;
    }
    
    

}

Employer Dao:

package hrms.northwind.dataAccess.abstracts;

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

import hrms.northwind.entities.concretes.Employer;

public interface EmployerDao extends JpaRepository<Employer,Integer>{

}

Employer Service:

package hrms.northwind.business.abstracts;

import java.util.List;

import org.springframework.stereotype.Service;

import hrms.northwind.entities.concretes.Employer;
@Service
public interface EmployerService {
    List<Employer> getAll();

}

Employer Controller:

package hrms.northwind.api.controllers;

import java.util.List;

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

import hrms.northwind.business.abstracts.EmployerService;
import hrms.northwind.entities.concretes.Employer;


@RestController
@RequestMapping("/api/employers")
public class EmployerController {
    private EmployerService employerService;
    @Autowired
    public EmployerController(EmployerService employerService) {
        super();
        this.employerService = employerService;
    }
    @GetMapping("/getall")
    public List<Employer> getAll(){
        return this.employerService.getAll();
    }
    
}

Employer Table:

Employer Table

Any help?

score 1 · Answer 1 · edited Aug 30 '22 at 06:33

1

Maybe is late for this answer

I think the problem comes from @Table. That annotation is optional when you want to specify an entity.

You could find better documented answer here

edited Aug 30 '22 at 06:33

Procrastinator

2,526
30
27
36

answered Aug 25 '22 at 08:54

Demelphy

11
2

score 0 · Answer 2 · answered Aug 30 '22 at 07:37

0

You can add this to your Employer class.

@Inheritance(strategy = InheritanceType.JOINED)
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
@PrimaryKeyJoinColumn(name="employer_id",referencedColumnName = "person_id")

answered Aug 30 '22 at 07:37

UmAvallac'h

1
1

Illegal use of @Table in a subclass of a SINGLE_TABLE hierarchy

2 Answers2