public  void onInitializeCollection(InitializeCollectionEvent event) throws HibernateException 
{
	         	 
		PersistentCollection collection = event.getCollection();
		SessionImplementor source = event.getSession();
		CollectionEntry ce = source.getPersistenceContext().getCollectionEntry(collection);
		if (ce==null) throw new HibernateException("collection was evicted");
		if ( !collection.wasInitialized() ) {
			if ( log.isTraceEnabled() ) {
				log.trace(
						"initializing collection " +
						MessageHelper.collectionInfoString( ce.getLoadedPersister(), ce.getLoadedKey(), source.getFactory() )
					);
			}
			log.trace("checking second-level cache");
			final boolean foundInCache = initializeCollectionFromCache(
					ce.getLoadedKey(),
					ce.getLoadedPersister(),
					collection,
					source
				);
			if (foundInCache) {
				log.trace("collection initialized from cache");
			}
			else {
				log.trace("collection not cached");
				ce.getLoadedPersister().initialize( ce.getLoadedKey(), source );
				log.trace("collection initialized");
				if ( source.getFactory().getStatistics().isStatisticsEnabled() ) {
					source.getFactory().getStatisticsImplementor().fetchCollection( 
							ce.getLoadedPersister().getRole() 
						);
				}
			}
		}
}

called by a collection that wants to initialize itself