Ricardo Martinelli Oliveira created HIBERNATE-139: ----------------------------------------------------- Summary: [HHH-7629] Initialize PersistentCollection with fetchType LAZY returns NPE Key: HIBERNATE-139 URL: https://issues.jboss.org/browse/HIBERNATE-139 Project: Hibernate Integration Issue Type: Support Patch Reporter: Ricardo Martinelli Oliveira Assignee: Steve Ebersole @JoinTable(name = "JOIN_TABLE", joinColumns = { @JoinColumn(name = "JOIN_TABLE_ID", referencedColumnName = "ID") }, inverseJoinColumns = { @JoinColumn(name = "ENTITY_ID", referencedColumnName = "ID") }) @ManyToMany(fetch = FetchType.LAZY) private Set<JoinTable> aProperty; When fetching this entity, and after initialize, I get all the valid attribute values but the aProperty is defined as PersistenceCollection. This collection is not intialized yet. When I initialize this collection as follow: (PersistentCollection) entity).forceInitialization(); Or Hibernate.initialize(entity); I got NullPointerException: Caused by: java.lang.NullPointerException at org.hibernate.engine.internal.StatefulPersistenceContext.getLoadedCollectionOwnerOrNull(StatefulPersistenceContext.java:790) at org.hibernate.event.spi.AbstractCollectionEvent.getLoadedOwnerOrNull(AbstractCollectionEvent.java:75) at org.hibernate.event.spi.InitializeCollectionEvent.<init>(InitializeCollectionEvent.java:36) at org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:1803) at org.hibernate.collection.internal.AbstractPersistentCollection.forceInitialization(AbstractPersistentCollection.java:489) at org.hibernate.Hibernate.initialize(Hibernate.java:77) When I check source code of class org.hibernate.engine.internal.StatefulPersistenceContext.getLoadedCollectionOwnerOrNull(StatefulPersistenceContext.java:790) CollectionEntry ce = getCollectionEntry( collection ); 790 if ( ce.getLoadedPersister() == null ) { 791 return null; // early exit... 792 } Looks like the CollectionEntry ce is null. This collection entry is fetched from collectionEntries.get(coll); // Identity map of CollectionEntry instances, by the collection wrapper 121 private IdentityMap<PersistentCollection, CollectionEntry> collectionEntries; I checked Jboss docs, it mentioned the way to initilialize the collection is as I have done above. http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/performance.htm... -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira