Proposed fix for https://hibernate.atlassian.net/browse/HSEARCH-1448

StatefulPersistenceContext.java.diff

diff --git a/hibernate-core/src/main/java/org/hibernate/engine/internal/StatefulPersistenceContext.java b/hibernate-core/src/main/java/org/hibernate/engine/internal/StatefulPersistenceContext.java
index 8ff72cd..8896aef 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/internal/StatefulPersistenceContext.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/internal/StatefulPersistenceContext.java
@@ -644,9 +644,18 @@
 								"proxy not of type HibernateProxy; it is " + proxyOrig.getClass()
 						);
 					}
+					
+					HibernateProxy hibernateProxyOrig = (HibernateProxy) proxyOrig ;
+					HibernateProxy hibernateProxy = ( (HibernateProxy) proxy );
+					
 					// set the read-only/modifiable mode in the new proxy to what it was in the original proxy
-					final boolean readOnlyOrig = ( (HibernateProxy) proxyOrig ).getHibernateLazyInitializer().isReadOnly();
-					( (HibernateProxy) proxy ).getHibernateLazyInitializer().setReadOnly( readOnlyOrig );
+					final boolean readOnlyOrig = hibernateProxyOrig.getHibernateLazyInitializer().isReadOnly();
+					hibernateProxy.getHibernateLazyInitializer().setReadOnly( readOnlyOrig );
+					
+					// if the original proxy was already initialized, set the implementation of the new proxy
+					if ( !hibernateProxyOrig.getHibernateLazyInitializer().isUninitialized() ) {
+						hibernateProxy.getHibernateLazyInitializer().setImplementation( hibernateProxyOrig.getHibernateLazyInitializer().getImplementation() );
+					}
 				}
 				return proxy;
 			}