[hibernate-issues] [Hibernate-JIRA] Created: (HHH-5087) A @ManyToOne field on the same entity class is null when 2nd level cache is enabled

[Joseph Pachod (JIRA)]

A @ManyToOne field on the same entity class is null when 2nd level cache is enabled
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                 Key: HHH-5087
                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5087
             Project: Hibernate Core
          Issue Type: Bug
          Components: caching (L2)
    Affects Versions: 3.5.0-Final, 3.3.0.CR1
            Reporter: Joseph Pachod
         Attachments: demos.tar.gz

The issue is based on this discussion https://forum.hibernate.org/viewtopic.php?p=2350265 which shows how to have a List with the index managed by Hibernate. 

The example given involves two distinct entities classes, for example ParentEntity.class et ChildEntity.class.

I tried to use it as well for a List containing the same entity, like that (see attachment for more details):
public class RecursiveListItem 
{
(..)
    public void setParent(final RecursiveListItem parent)
    {
        this.parent = parent;
    }

    public RecursiveListItem getParent()
    {
        return parent;
    }

    public static final String RECURSIVELISTITEM_ONETOMANY_INDEX_COLUMN_NAME = "recursivelistitem_position";
    public static final String RECURSIVELISTITEM_ONETOMANY_JOIN_COLUMN_NAME = "recursivelistitem_id";

    @ManyToOne
    @JoinColumn(name = RECURSIVELISTITEM_ONETOMANY_JOIN_COLUMN_NAME, insertable = false, updatable = false)
    private RecursiveListItem parent;
    @SuppressWarnings("unused")
    @Column(name = RECURSIVELISTITEM_ONETOMANY_INDEX_COLUMN_NAME, insertable = false, updatable = false)
    private Integer position;

    @OneToMany(fetch = FetchType.LAZY)
    @JoinColumn(name = RecursiveListItem.RECURSIVELISTITEM_ONETOMANY_JOIN_COLUMN_NAME)
    @org.hibernate.annotations.IndexColumn(name = RecursiveListItem.RECURSIVELISTITEM_ONETOMANY_INDEX_COLUMN_NAME)
    private List<RecursiveListItem> children = new ArrayList<RecursiveListItem>();

(...)
}

In my test case, I do :
		EntityManager entityManager = entityManagerFactory.createEntityManager();
	
		RecursiveListItem parent = new RecursiveListItem();
		RecursiveListItem child = new RecursiveListItem();
		
		persist(entityManager, parent);
		persist(entityManager, child);
		
		parent.getChildren().add(child);
		child.setParent(parent);
		
		persist(entityManager, parent);
		persist(entityManager, child);
		
		entityManager.close();
		
		entityManager = entityManagerFactory.createEntityManager();
		RecursiveListItem childFound = entityManager.find(RecursiveListItem.class, child.getId());
		assertNotNull(childFound);
		assertNotNull(childFound.getParent());

The last line works when the 2nd level cache and fails otherwise.

The issue applies both for 3.5 and 3.3.0.CR1. In the attached file I put two maven enabled eclipse projects, on for 3.5 and one for 3.3.0.CR1.

Thanks in advance

best regards
joseph

ps : I'll be on vacation until next Monday (April 12)

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