[hibernate-issues] [Hibernate-JIRA] Closed: (HHH-1095) Hibernate takes incorrect HasCode when a lot of CompositeKeys and Lazy loading is involved

Hibernate takes incorrect HasCode when a lot of CompositeKeys and Lazy loading is involved ------------------------------------------------------------------------------------------ Key: HHH-1095 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1095 Project: Hibernate Core Issue Type: Patch Affects Versions: 3.1 rc2 Environment: Hibernate 3.0.5 and 3.1-cvs Reporter: Konstantin Ignatyev Fix For: 3.1 rc3 Attachments: EntityType.java.3.0.5.patch, EntityType.java.3.1.patch, sup7repro.zip The problem is that when trying to load the OrderLines collection from an Order, the set came back as being empty, which it should not have. It is important to note that Order has a composite primary key composed of order_id and District. This is encapsulated in an OrderId class. District has a composite primary key composed of d_id and Warehouse, this is encapsulated in a districtId class. Warehouse has an integer as it's primary key. OrderLine has a composite primary key that is composed of Order and ol_number (which is a short). This is encapsulated in an OrderLineId class. Each of the custom classes that represents a composite primarey key has hash() and equals() overridden. The problem we seem to be running into is that when Hibernate loads the collection for this object it first runs through and creates an emply collection in the CollectionLoadingContext. It does this with the OrderId it gets from the PersistantColleciton, which is already fully loaded and has an actual District rather that a proxied District. Then when we process our query results we get back into getLoadingCollection with the OrderId we read from the ResultSet. The problem here is that the District it has is proxied. So the fix for that is to change EntityType#getHashCode function like this: public int getHashCode(Object x, EntityMode entityMode, SessionFactoryImplementor factory) { EntityPersister persister = factory.getEntityPersister(associatedEntityName); if ( !persister.hasIdentifierPropertyOrEmbeddedCompositeIdentifier() ) { return super.getHashCode(x, entityMode); } Serializable id; if (x instanceof HibernateProxy) { id = ( (HibernateProxy) x ).getHibernateLazyInitializer().getIdentifier(); } else { id = persister.getIdentifier(x, entityMode); } return persister.getIdentifierType().getHashCode(id, entityMode, factory); } The attached files include: - a test case to reproduce the problem: run by Maven1 with command maven jar. The error report gets created under target. The maven assumes that there is j2ee-1.3.1.jar file is in local Maven repository. - couple of patches, one for 3.0.5 and another for 3.1