Hibernate MappingException: Unknown entity: com.xxxxxx.service.model.$Proxy$_$$_WeldClientProxy

Question

I'm using maven multimodule project. I divided my logic into different layers, Presentation, Business logic, data layer, each one in a separate module(layer). When I try to insert an object, this exception occurs:

org.hibernate.MappingException: Unknown entity: com.xxxxx.service.model.Object$Proxy$_$$_WeldClientProxy

How is this caused and how can I solve it?

I'm using CDI bean and the application is based on JSF2 and Hibernate.

Answer 1

This problem will happen when you have a JPA entity which is also declared as a CDI managed bean like below:

@Named // Or @XxxScoped
@Entity
public class YourEntity {}

And you attempt to persist the CDI managed bean instance itself like below:

@Inject
private YourEntity yourCDIManagedEntity;

@PersistenceContext
private EntityManager entityManager;

public void save() {
    entityManager.persist(yourCDIManagedEntity);
}

This is not the correct way. You should not make your entity a CDI managed bean. A CDI managed bean is actually a proxy class. You can clearly see this back in your exception message. It says it doesn't know the entity com.xxxxx.service.model.Object$Proxy$_$$_WeldClientProxy instead of that it doesn't know the entity com.xxxxx.service.model.Object.

@Entity // NO @Named nor @XxxScoped!
public class YourEntity {}

And you should prepare it as a normal entity instance and then you can safely persist it as a normal entity.

private YourEntity yourNormalEntity;

@PersistenceContext
private EntityManager entityManager;

@PostConstruct
public void init() {
    yourNormalEntity = new YourEntity();
}

public void save() {
    entityManager.persist(yourNormalEntity);
}