Hello,
I'm using JPA/Hibernate version: 3.2 in my project. Recently I'm seeing following error when Collection of object is received(which is lazily initialized).Though Entity manager is NOT closed at that point of code, I'm surprised/confused on how this error is thrown. More over this error is not consistent. any help would be highly appreciated. Thanks.

no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:358)
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:350)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:343)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentBag.iterator(PersistentBag.java:249)

? It can hardly be a surprise that if you close the persistence context, you get an exception saying "it is closed" when you try to use it again (illegally)? You can't continue loading stuff from the database on-demand once the persistence context is closed. Read http://hibernate.org/43.html or really anything about lazy loading/persistence context handling.

Thanks christian for your reply.

I'm sorry. I missed "NOT" in my first thread.
It should have been: Though Entity manager is NOT closed at that point of code, I'm surprised/confused on how this error is thrown. Could you please help ?

It's very unlikely that there is a bug in this area, but if you can reproduce the issue in a simple minimal test case, post it to JIRA.

Hi,
I am seeing something similar, I clear the persistence context and then invoke a size operation on a 1M relationship:



I get:

com.fineos.ta3g.test.jpatests.JPASqlAnalysis.test_1Morg.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.fineos.ta3g.test.garage.Company.employees, no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:358)
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:350)
at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:97)
at org.hibernate.collection.PersistentBag.size(PersistentBag.java:225)
at com.fineos.ta3g.test.jpatests.JPASqlAnalysis.test_1M(JPASqlAnalysis.java:111)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

... which is expected, since your object is detached (ie not associated to a session)

Thanks! Yes. I was calling em.clear() which detaches all the object.
I'm using hibernate annotations. I know that we have session.evict(object) to clear particular object. Do we have same kind of function in entitymanager? if not , Then I should use
org.hibernate.Session session = ((org.hibernate.ejb.HibernateEntityManager)em).getSession();
session.evict(object);

Also I want to know how I can do cascade evict in annotations.

Thanks again!

Interesting and thanks for that.
If it's evicted from the session, it's surely then just a normal API (i.e. non JPA) being invoked on a Java object.
I would have thought it should have just returned something like it does when the object is transient and not throw a hibernate exception.

Not sure what other people think, but the behaviour seems counter intuitive to me.

Is this behaviour standard JPA or is it something Hibernate adds on?

Many many thanks
Breako

Just an update on this issue, I didn't see this behaviour when using
an older version of the Entity Manager.
I did not see this behaviour when I was using:

Annotations: Version: 3.2.0 CR1
Core: version 3.2 cr2
EntityManager: Version: 3.2.0.CR1

but do see it when using the following versions:

Annotations: Version: 3.3.0.GA
Core: version 3.2.3 GA
EntityManager: 3.3.1.GA

As it is not clear what version if I am on the same versions as techluver
I might take this in a separate post.

Section 3.2.4 of the spec explains what state is still available in a detached entity. About associations that a detached entity has, it says:
So if the associated instance isn't available, it is *unsafe* to access it, and an error like you are getting is reasonable.
--keenan

your transient object is different, it has no association with lazy objects usually

The behavior has always been the same but the object loading might have changed, there were some bugs in previous HEM versions that forced unneeded initializations (having the object eagerly loaded where lazy was expected).

Sorry to drag up this old topic... but it is probably relevant for people searching google on this issue.

In the case being discussed by breako, does anyone else think that the error message is a bit misleading?



After all, the session still exists and is still open, the problem is that the object is not in the hibernate cache any more.

sorry for rise the thread again. I am having a similiar problem.

I have a User object that has many Houses. The fetch type is LAZY
This is how I reproduce the issue:

1. Open Session
2. Fetch User object
3. Close the Session.
4. Make some operations with the User object (and now, I want the user's houses, so I call user.getHouses():
5. Open a new session
6. Call user.getHouses()

then I got failed to lazily initialize a collection of role: User.houses, no session or session was closed

Already tried those, with no sucess:
1. call session.refresh(user) before call user.getHouses()
2. open a transaction before user.getHouses()
3. call session.lock(user, NONE) before user.getHouses()