strange non repeatable NullPointerException

ollie · **Joined:** Fri Dec 05, 2003 12:44 am **Posts:** 16

Hello,

I'm occasionally getting the following NPE exception when I try to load an object. Also, strangely, if I do the same load directly after one that caused an exception the second load will always be successful.

Any clues about what could be causing this?

I'm using Spring to manage transactions/session.

Code:

java.lang.NullPointerException
   at net.sf.hibernate.collection.PersistentCollection.forceInitialization(PersistentCollection.java:331)
   at net.sf.hibernate.impl.SessionImpl.initializeNonLazyCollections(SessionImpl.java:3007)
   at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:137)
   at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:830)
   at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:850)
   at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:57)
   at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:49)
   at net.sf.hibernate.persister.EntityPersister.load(EntityPersister.java:420)
   at net.sf.hibernate.impl.SessionImpl.doLoad(SessionImpl.java:2044)
   at net.sf.hibernate.impl.SessionImpl.doLoadByClass(SessionImpl.java:1918)
   at net.sf.hibernate.impl.SessionImpl.load(SessionImpl.java:1847)
   at ourcommunity.util.hibernate.HibernateHelper$1.doInHibernate(HibernateHelper.java:49)
   at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:147)
   at ourcommunity.util.hibernate.HibernateHelper.get(HibernateHelper.java:44)
   at ourcommunity.newsletter.dao.NewsletterDAO.findEditionVariation(NewsletterDAO.java:67)
   .
   .
   .

Mapping is this

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
    PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
    <class name="ourcommunity.newsletter.dao.EditionVariationDO" table="NewsletterEditionVariation"              
            select-before-update="true"
            dynamic-update="true">

        <cache usage="read-write" /> 
    
        <id name="id" type="int" column="ID" unsaved-value="0" >
            <generator class="identity"/>
        </id>
        
        <version name="version" />

        <property name="status" column="Status" />
   <property name="variation" column="Variation" />
   <property name="deliveryOption" column="DeliveryOption" />
   <property name="bulkEmailId" column="BulkEmailID" />
   <property name="editionId" column="NewsletterEditionID" />
    </class>
</hibernate-mapping>

emmanuel · **Posted:** Fri Jan 16, 2004 6:28 am

Hum, that's strange, it seems that the session associated to this collection was closed. Does it sounds familiar in your app ?

gavin · **Posted:** Fri Jan 16, 2004 6:07 pm

Actually it seems like the collection does not have a reference to any session. How did this come about? Something to do with serialization?

ollie · **Joined:** Fri Dec 05, 2003 12:44 am **Posts:** 16

Tracked this one down to some silly old code left over from when I was using Castor for ORM.

In one of the setters of EditionVariationDO there was some code that manually loaded a related object. This meant that the session was getting called recursively and I'd say that really messed with some of the internal state. Obviously the recursive call was successful but it's caused problems down the line for the original call.