Fix a subtle double-checked locking issue

hibernate · Mar 19, 2020 · df0aa1e · df0aa1e
1 parent 620dcc6
commit df0aa1e
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/...te-core/src/main/java/org/hibernate/persister/collection/AbstractCollectionPersister.java b/...te-core/src/main/java/org/hibernate/persister/collection/AbstractCollectionPersister.java
@@ -744,18 +744,21 @@ protected void logStaticSQL() {
 		}
 	}
 
-	private CollectionLoader standardCollectionLoader;
+	private volatile CollectionLoader standardCollectionLoader;
 
 	@Override
 	public void initialize(Object key, SharedSessionContractImplementor session) throws HibernateException {
 //		getAppropriateInitializer( key, session ).initialize( key, session );
 		determineLoaderToUse( key, session ).load( key, session );
 	}
 
+	// lazily initialize instance field via 'double-checked locking'
+	// see https://en.wikipedia.org/wiki/Double-checked_locking
 	protected CollectionLoader getStandardCollectionLoader() {
 		CollectionLoader localCopy = standardCollectionLoader;
 		if ( localCopy == null ) {
 			synchronized (this) {
+				localCopy = standardCollectionLoader;
 				if ( localCopy == null ) {
 					localCopy = createCollectionLoader( LoadQueryInfluencers.NONE );
 					standardCollectionLoader  = localCopy;