Hibernate MappingException while using annotation #Inheritance with MySql - mysql

Question

I'am using Hibernate framework 3.6.10.Final and MySql. I'am getting
Exception in thread "main" org.hibernate.MappingException: Cannot use identity column key generation with mapping for: org.koushik.javabrains.dto.Vehicle
when am including #Inheritance(strategy=InheritanceType.TABLE_PER_CLASS) in vehicle class. It's working fine with out this annotation.
Vehicle.java is my base class:
#Entity
#Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public class Vehicle
{
#Id
#GeneratedValue
private int vehicleId;
private String vehicleName;
public int getVehicleId() {
return vehicleId;
}
public void setVehicleId(int vehicleId) {
this.vehicleId = vehicleId;
}
public String getVehicleName() {
return vehicleName;
}
public void setVehicleName(String vehicleName) {
this.vehicleName = vehicleName;
}
}
TwoWheeler.java:
#Entity
public class TwoWheeler extends Vehicle {
private String SteeringHandle;
public String getSteeringHandle() {
return SteeringHandle;
}
public void setSteeringHandle(String steeringHandle) {
SteeringHandle = steeringHandle;
}
}
FourWheeler.java:
#Entity
public class FourWheeler extends Vehicle {
private String SteeringWheel;
public String getSteeringWheel() {
return SteeringWheel;
}
public void setSteeringWheel(String steeringHandle) {
SteeringWheel = steeringHandle;
}
}
My main class:
public class HibernateTest {
public static void main(String[] args)
{
Vehicle vehicle = new Vehicle();
vehicle.setVehicleName("audi"+(int)(Math.random() * 100) + 1);
TwoWheeler bike = new TwoWheeler();
bike.setVehicleName("bike");
bike.setSteeringHandle("Bike SteeringHandle");
FourWheeler car = new FourWheeler();
car.setVehicleName("car");
car.setSteeringWheel("Car SteeringHandle");
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(vehicle);
session.save(bike);
session.save(car);
session.getTransaction().commit();
session.close();
}
}
And when am running am getting following error:
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Exception in thread "main" org.hibernate.MappingException: Cannot use identity column key generation with mapping for: org.koushik.javabrains.dto.Vehicle
at org.hibernate.persister.entity.UnionSubclassEntityPersister.(UnionSubclassEntityPersister.java:90)
at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:90)
at org.hibernate.impl.SessionFactoryImpl.(SessionFactoryImpl.java:286)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1872)
at org.koushik.hibernate.HibernateTest.main(HibernateTest.java:26)

Answer 1

if you use TABLE_PER_CLASS, you have to use this ID generation strategy: #GeneratedValue(strategy
= GenerationType.TABLE)

Answer 2

Vehicle.java
#Entity
#Table(name="vehicle")
#Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public class Vehicle
{
#Id
#GeneratedValue(strategy=GenerationType.TABLE)
#Column(name="vehicle_id")
private int vehicleId;
#Column(name="vehicle_name")
private String vehicleName;
public int getVehicleId() {
return vehicleId;
}
public void setVehicleId(int vehicleId) {
this.vehicleId = vehicleId;
}
public String getVehicleName() {
return vehicleName;
}
public void setVehicleName(String vehicleName) {
this.vehicleName = vehicleName;
}
}