Hi,

I'm getting these because during the creation of my POJO domain object graph, setter methods get called which need to access a collection which is currently being lazily initialized and hasn't finished yet.

I'm preventing this by adding Hibernate.isInitialized(collection) into the domain object's setX method which is trying to access the collection.

This seems extremely invasive though. Is there anyway I can do this outside of my POJO domain objects? I'd like to get the entity with it's collection pre-initialized if possible (ie. NOT lazily).

I've tried immediateLoad(objectOwningCollection) on SessionImplementor interface and also making an explicit call to initialize(objectOwningCollection) after I've loaded it but neither of these work.

Any of you experts done this before?

thanks,

Neil

Is your collection configured with lazy="false"?
see:
http://www.hibernate.org/hib_docs/v3/re ... ns-mapping

Based on the title, I'm assuming that you're using Hibernate 2.x ?

The LazyInitializationException should only be thrown when the Session has been closed and the collection can not be initialized at all. You should not have a problem with collections that aren't completely initialized yet.

Thanks for the suggestion Preston but I'm pretty sure my session is still open and that I'm in the middle of a load call. I'm using Hibernate 2.1 and Spring Framework to manage sessions. Here's my stack trace:

org.springframework.orm.hibernate.HibernateSystemException: exception setting property value with CGLIB (set hibernate.cglib.use_reflection_optimizer=false for more info) setter of org.thorne.lettings.referencedata.api.AddressImpl.setArea; nested exception is net.sf.hibernate.PropertyAccessException: exception setting property value with CGLIB (set hibernate.cglib.use_reflection_optimizer=false for more info) setter of org.thorne.lettings.referencedata.api.AddressImpl.setArea
net.sf.hibernate.PropertyAccessException: exception setting property value with CGLIB (set hibernate.cglib.use_reflection_optimizer=false for more info) setter of org.thorne.lettings.referencedata.api.AddressImpl.setArea
at net.sf.hibernate.persister.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:221)
at net.sf.hibernate.impl.SessionImpl.initializeEntity(SessionImpl.java:2223)
at net.sf.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:315)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:305)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:990)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:965)
at net.sf.hibernate.loader.OneToManyLoader.initialize(OneToManyLoader.java:93)
at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:288)
at net.sf.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:3303)
at net.sf.hibernate.collection.PersistentCollection.forceInitialization(PersistentCollection.java:336)
at net.sf.hibernate.impl.SessionImpl.initializeNonLazyCollections(SessionImpl.java:3156)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:138)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:911)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:931)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:59)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:51)
at net.sf.hibernate.persister.EntityPersister.load(EntityPersister.java:415)
at net.sf.hibernate.impl.SessionImpl.doLoad(SessionImpl.java:2130)
at net.sf.hibernate.impl.SessionImpl.doLoadByClass(SessionImpl.java:2000)
at net.sf.hibernate.impl.SessionImpl.load(SessionImpl.java:1929)
at org.springframework.orm.hibernate.HibernateTemplate$3.doInHibernate(HibernateTemplate.java:291)
at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:243)
at org.springframework.orm.hibernate.HibernateTemplate.load(HibernateTemplate.java:289)
at org.thorne.lettings.referencedata.service.HibernateDataManagementService.find(HibernateDataManagementService.java:33)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:296)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:163)
at $Proxy0.find(Unknown Source)
at ContactAssociationTest.testContactListenerAdditionToAddress(ContactAssociationTest.java:96)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at com.intellij.rt.execution.junit2.JUnitStarter.main(JUnitStarter.java:31)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:78)
Caused by: net.sf.cglib.beans.BulkBeanException: cannot access loading collection
at org.thorne.lettings.referencedata.api.AddressImpl$$BulkBeanByCGLIB$$8c13d8c8.setPropertyValues(<generated>)
at net.sf.hibernate.persister.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:216)
... 55 more
Caused by: net.sf.hibernate.LazyInitializationException: cannot access loading collection
at net.sf.hibernate.collection.PersistentCollection.initialize(PersistentCollection.java:191)
at net.sf.hibernate.collection.PersistentCollection.write(PersistentCollection.java:84)
at net.sf.hibernate.collection.Set.add(Set.java:154)
at org.thorne.lettings.referencedata.api.AreaImpl.addAddress(AreaImpl.java:45)
at org.thorne.lettings.referencedata.api.AddressImpl.setArea(AddressImpl.java:100)
... 57 more


As you can hopefully see, I'm getting the exception within a call to SessionImpl.load, so I assume the session is still open when then call is begin made. The problem is I think, that I'm trying to manage the object graph myself in a bidirectional parent/child relationship at both ends.

The child end (address) has had it's parent (area) set and is now trying to add itself as an Address to the area. The area then accesses it's collection where the exception occurs.

This is the opposite case I have seen in the 2.1 docs where the parent end has a child added and the parent sets itself as the parent of the child.

"set hibernate.cglib.use_reflection_optimizer=false for more info"

Did you do that?

Yes I did try that (but maybe not correctly - I did it via Spring)

<bean id="sessionFactoryInstance" class="org.springframework.orm.hibernate.LocalSessionFactoryBean">
<property name="mappingResources">
<list>
<value>tenant.hbm.xml</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">net.sf.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.use_outer_join">false</prop>
<prop key="hibernate.jdbc.use_get_generated_keys">false</prop>
<prop key="hibernate.cglib.use_reflection_optimizer">false</prop>
</props>
</property>
<property name="dataSource">
<ref bean="dataSource"/>
</property>
</bean>

But I got no more info - I take it I can set this property as I have above?

I should also point out that I've tried setting lazy="false" and this doesn't fix the problem.

I don't think it'll be solved by HOW a retrieve the collection.

The problem is that as hibernate loads each child member of the parent, it sets the parent attribute on the child. If the child then tries to add itself to that parent the collection will be accessed mid-load.

Read the documentation and set the property either via hibernate.properties or as a system property. No idea what the Spring wrapper stuff does.

Hi,
system property

hibernate.cglib.use_reflection_optimizer=false

was set and the stack trace is this:

org.springframework.orm.hibernate.HibernateSystemException: Exception occurred inside setter of org.thorne.lettings.referencedata.api.AddressImpl.area; nested exception is net.sf.hibernate.PropertyAccessException: Exception occurred inside setter of org.thorne.lettings.referencedata.api.AddressImpl.area
net.sf.hibernate.PropertyAccessException: Exception occurred inside setter of org.thorne.lettings.referencedata.api.AddressImpl.area
at net.sf.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:49)
at net.sf.hibernate.persister.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:230)
at net.sf.hibernate.impl.SessionImpl.initializeEntity(SessionImpl.java:2223)
at net.sf.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:315)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:305)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:990)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:965)
at net.sf.hibernate.loader.OneToManyLoader.initialize(OneToManyLoader.java:93)
at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:288)
at net.sf.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:3303)
at net.sf.hibernate.collection.PersistentCollection.forceInitialization(PersistentCollection.java:336)
at net.sf.hibernate.impl.SessionImpl.initializeNonLazyCollections(SessionImpl.java:3156)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:138)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:911)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:931)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:59)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:51)
at net.sf.hibernate.persister.EntityPersister.load(EntityPersister.java:415)
at net.sf.hibernate.impl.SessionImpl.doLoad(SessionImpl.java:2130)
at net.sf.hibernate.impl.SessionImpl.doLoadByClass(SessionImpl.java:2000)
at net.sf.hibernate.impl.SessionImpl.load(SessionImpl.java:1929)
at org.springframework.orm.hibernate.HibernateTemplate$2.doInHibernate(HibernateTemplate.java:459)
at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:357)
at org.springframework.orm.hibernate.HibernateTemplate.load(HibernateTemplate.java:453)
at org.springframework.orm.hibernate.HibernateTemplate.load(HibernateTemplate.java:448)
at org.thorne.lettings.referencedata.service.HibernateDataManagementService.find(HibernateDataManagementService.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:292)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:163)
at $Proxy0.find(Unknown Source)
at ContactAssociationTest.testStackOverflow4(ContactAssociationTest.java:27)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at com.intellij.rt.execution.junit2.JUnitStarter.main(JUnitStarter.java:31)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:78)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at net.sf.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:38)
... 57 more
Caused by: net.sf.hibernate.LazyInitializationException: cannot access loading collection
at net.sf.hibernate.collection.PersistentCollection.initialize(PersistentCollection.java:191)
at net.sf.hibernate.collection.PersistentCollection.write(PersistentCollection.java:84)
at net.sf.hibernate.collection.Set.add(Set.java:154)
at org.thorne.lettings.referencedata.api.AreaImpl.addAddress(AreaImpl.java:45)
at org.thorne.lettings.referencedata.api.AddressImpl.setArea(AddressImpl.java:100)
... 62 more

And if you wouldn't use the stupid Spring wrapper you'd see what the nested exception really is. It's in your code, so nobody here can tell you what it could be.

I see this is "net.sf.hibernate.LazyInitializationException", it looks like you are using spring in the wrong way.

Okay - so even if I take Spring out of the picture:


it's basically exactly the same exception.

And now I've upgraded to Hibernate3.

Now without me resorting to posting a lot of code a simple explanation of this is that I'm simply doing a session.get() for a known parent object, which participates in a one-to-many parent child relationship.

I've coded up some simple methods on the parent which go like:

public void addChild(Child c){
this.collection.add(c);
c.setParent(this);
}

and here's the important bit, where I think the problem lies: I've also coded some simple methods on the child which go like:

public void setParent(Parent p){
this.parent = p;
p.addChild(this);
}


this is what I've not seen before in the examples - where a change in the child's parent means the child tries to add itself as a child to that parent.


Now I've got some other bits in there to stop a recursive loop, but from the stack trace I can see this:



so Area is the parent and Address is the child.

It looks to me that when I ask the session to get the parent, it is setting up the relationships with setArea calls on the Addresses. That in turn results in a call to addAddress on the Area as outlined in the parent/child snippet above.

This causes an access of the underlying collection on the parent which throws the exception.

Now, am I wrong to try and manage parent relationships from a child? And is this what the problem is? As I've mentioned before, I can temporarily disable this by adding a Hibernate.isInitialized(area.getAddresses()) to the child's setArea method but this is a bad dependency for me.

Read the "Parent/Child example" chapter in the reference documentation. It recommends to _add_ a method that handles the bidirectional relationship. It does not say: Do it in your setter so you get funny side effects.

Okay, now I see what you're saying.

Don't do relationship management in any methods that hibernate is expecting to use because you'll get side effects.

Thank you very much for your help Christian.