[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-3854) Issue with greedy loading of associations (default-lazy=false )

[Erik-Berndt Scheper (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-3854?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=33698#action_33698 ] 

Erik-Berndt Scheper commented on HHH-3854:
------------------------------------------

I see the same NPE with JPA / annotations, but only if the persistent object is a final class.

The reason behind this is that the proxyFactory is null (as above), because the constructor of EntityMetaModel.class (in hibernate core) then declares it as non-lazy (line 267-271 in EntityMetaModel.java, hibernate-core-3.3.2.GA):

		lazy = persistentClass.isLazy() && (
				// TODO: this disables laziness even in non-pojo entity modes:
				!persistentClass.hasPojoRepresentation() ||
				!ReflectHelper.isFinalClass( persistentClass.getProxyInterface() )
		);


Becayse the entityMetamodel is NOT lazy for final classes the constructor of the AbstractEntityTuplizer (i.e. any tuplizer) will set the proxyFactory to null (line 150-158 in AbstractEntityTuplizer .java, hibernate-core-3.3.2.GA):

		if ( entityMetamodel.isLazy() ) {
			proxyFactory = buildProxyFactory( mappingInfo, idGetter, idSetter );
			if (proxyFactory == null) {
				entityMetamodel.setLazy( false );
			}
		}
		else {
			proxyFactory = null;
		}


This all eventually leads to a NPE in hibernate envers ToOneIdMapper.class

java.lang.NullPointerException
	at org.hibernate.tuple.entity.AbstractEntityTuplizer.createProxy(AbstractEntityTuplizer.java:394)
	at org.hibernate.persister.entity.AbstractEntityPersister.createProxy(AbstractEntityPersister.java:3469)
	at org.hibernate.envers.entities.mapper.relation.ToOneIdMapper.mapToEntityFromMap(ToOneIdMapper.java:84)
	at org.hibernate.envers.entities.mapper.MultiPropertyMapper.mapToEntityFromMap(MultiPropertyMapper.java:117)
	at org.hibernate.envers.entities.EntityInstantiator.createInstanceFromVersionsEntity(EntityInstantiator.java:93)
	at org.hibernate.envers.entities.EntityInstantiator.addInstancesFromVersionsEntities(EntityInstantiator.java:103)
	at org.hibernate.envers.query.impl.EntitiesAtRevisionQuery.list(EntitiesAtRevisionQuery.java:90)
	at org.hibernate.envers.query.impl.AbstractAuditQuery.getSingleResult(AbstractAuditQuery.java:104)
	at org.hibernate.envers.reader.AuditReaderImpl.find(AuditReaderImpl.java:104)
<rest of trace skipped>

> Issue with greedy loading of associations (default-lazy=false )
> ---------------------------------------------------------------
>
>                 Key: HHH-3854
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3854
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: envers
>         Environment: Hibernate - core 3.4.0-SNAPSHOT, Hibernate-envers (from trunk)
>            Reporter: Amar Singh
>         Attachments: greedy-loading.zip
>
>
> I have an Entity GP which has a many to one association to entity CA.
> <?xml version="1.0"?>
> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
>                                    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
> <hibernate-mapping package="org.hibernate.envers.test.integration.onetoone.bidirectional" default-lazy="false">
> <class name="BidirectionalRefIngPK" table="BIDIRECTIONAL_REFERENCING_ENTITY">
>   <id name="id" type="long" column="BIDIRECTIONAL_REFERENCING_ID" >
>    	<generator class="native"/>
>   </id>
>   <property name="data"/>
>   <many-to-one name="reference" cascade="save-update" class="BidirectionalRefEdPK" column="BIDIRECTIONAL_REFERENCED_ID"/>
>  </class>
>  
>  <class name="BidirectionalRefEdPK" table="BIDIRECTIONAL_REFERENCED_ENTITY">
>   <id name="longId" type="long" column="BIDIRECTIONAL_REFERENCED_ID">
>    <generator class="native"/>
>   </id>
>   <property name="data"/>
>  </class>
>  
> </hibernate-mapping>
> With this when I load a previous version of BidirectionalRefIngPK, the loading mechanism tries to create a proxy for BidirectionalRefEdPK, but in my case lazy is false so an internal call to createProxy will return NULL hence .
> This happens in ToOneIdMapper.java in method mapToEntityFromMap around line 82, which then internally calls for AbstractEntityTuplizer.java line 395 for getProxyFactory() ending in NULL pointer exception because proxy factory is null as mine is a greedy loading. 
> TO REPRODUCE
> ~~~~~~~~~~~~~
> Please find a zipped folder attached. The zipped file has 4 files:
> - GreedyLoading.java (actual testng test case)
> - BidirectionalRefEdPK.java (Entity 1)
> - BidirectionalRefIngPK.java (Entity 2)
> - greedyloading.hbm.xml
> Please place the three java files in its package (org.hibernate.envers.test.integration.onetoone.bidirectional), couldn't find the right package so created test case accordingly. Put the greedyloading.hbm.xml in src/test/resources.
> Now when testng runs GreedyLoading.java you should see NPE.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira