FetchType.EAGER - what's wrong with my annotations?

zywno · **Posted:** Mon Jan 30, 2006 1:18 pm

Hi,

I have a simple relationship that is configured(AFAIK) to use eager loading of associated collection - I want to load the data eagerly to be able to use getters after a session is closed.

Code:

@Entity()
@Table(name = "user")
public class User {

   @OneToMany(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
   public Set<Place> getPlaces() {
      return places;
   }
}

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "placetype", discriminatorType = DiscriminatorType.STRING)
@Table(name = "place")
public abstract class Place {

   @ManyToOne(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
   @JoinColumn(nullable = false)
   public User getUser() {
      return user;
   }
}

However when a user is loaded it is of a proxy type and the places set in not initialized. I get a well known "org.hibernate.LazyInitializationException: could not initialize proxy - the owning Session was closed" when invoking a getPlaces method.

Could you give me any hint of how to properly configure eager loading. (As you can see in the code fetch = FetchType.EAGER is set - but is it correctly set?)

Thanks,

Maciek

emmanuel · **Posted:** Mon Jan 30, 2006 1:26 pm

I find it hard to believe. There are unit tests for EAGER fetching in Hibernate Annotations, have a look

zywno · **Posted:** Tue Jan 31, 2006 7:53 am

To give you more details:

The exception occurs when a getter is invoked when a session is already closed. I don't know Hibernate well and don't know if it is correct, but a user object returned is of proxy type. Afterwards when a getter is invoked a CGLIBLazyInitializer.intercept and AbstractLazyInitializer is invoked which throws the exception.

When I added @Proxy(lazy=false) in both a User and a Place class the eager loading works.

Code:

@Entity()
@Table(name = "user")
@Proxy(lazy = false)
public class User {..}

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "placetype", discriminatorType = DiscriminatorType.STRING)
@Table(name = "place")
@Proxy(lazy = false)
public abstract class Place {}

Where do you suggest to take a look at in the debuggger to find what;s wrong?

Thanks,

Maciek

h.b. · **Joined:** Wed Apr 13, 2005 10:34 am **Posts:** 38

I don't think, the association to Places is your problem.
As you wrote, the instance of User is already a proxy.

I'd guess you are using Session.load() to retrieve the User.
The method load() always returns a proxy - even if the is no persistent instance with the given identifier. Use Session.get() instead.

zywno · **Posted:** Tue Jan 31, 2006 12:48 pm

Yes, you're right. I used sesion.load. After switching to session.get it started working :)

Thanks,

Maciek

emmanuel · **Posted:** Wed Feb 01, 2006 4:53 am

so please rate him