HibernateException: Found two representations of same collection

Question

If I save an object containing the following list

@OneToMany(cascade=CascadeType.ALL, mappedBy="taskList")
@OrderColumn(name="position", nullable=false)
public List<Task> tasks = new ArrayList<Task>();

I get the exception

org.hibernate.HibernateException: Found two representations of same collection

The code in the Play! controller looks like this:

TaskList taskList = taskList.findById(taskListId);
taskList.add(position, task);
taskList.save();

If I insert taskList.refresh() before this block it works, but the position information is lost (which leads to other errors).

Is this a Hibernate bug or is something wrong with my code?

score 13 · Accepted Answer · edited May 23 '17 at 11:54

13

The problem was, that Hibernate does not support the combination of @OneToMany(mappedBy=...) and @OrderColumn. Without mappedBy Hibernate uses a join table and everything works as expected. See explanation.

edited May 23 '17 at 11:54

Community

1
1

answered Nov 30 '11 at 20:16

deamon

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score 2 · Answer 2 · answered Aug 02 '17 at 15:06

The same error occurs when you try to modify an associated collection of an object. e.g.:

    MyObject myObject = myObjectService.get(id);
    List<Task> newTasks = //populate new list of Task here
    myObject.setTasks(newTasks);
    myObjectService.saveOrUpdateObject(myObject); // or merge(myObject)

In such a case, it can be resolved by:

    MyObject myObject = myObjectService.get(id);
    List<Task> newTasks = //populate new list of Task here
    myObject.setTasks(new List<Task>); // or myObject.getTasks().clear();
    myObject.getTasks().addAll(newTasks);
    myObjectService.merge(myObject);

score 1 · Answer 3 · answered Sep 29 '20 at 13:48

1

I could resolve the issue by changing the association to lazy and removing the cascade.

@OneToMany(mappedBy="taskList", fetch = FetchType.LAZY)
@OrderColumn(name="position", nullable=false)
public List<Task> tasks = new ArrayList<Task>();

answered Sep 29 '20 at 13:48

Gat

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Removing FetchType.EAGER worked for while retaining the CascadeType.ALL operation. – Ruben Vervaeke Dec 18 '20 at 13:36

score 0 · Answer 4 · answered Feb 15 '13 at 19:06

0

Another reason for the exception "org.hibernate.HibernateException: Found two representations of same collection" is duplicated getters/setters in the entity.

answered Feb 15 '13 at 19:06

adelarsq

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score 0 · Answer 5 · answered Jun 23 '20 at 16:04

After a lot of hours I found the solution, I had the same problem.

I had an EntityListener with this code in my Spring Boot app

@PostLoad
public void defineRelation(EntityWithRelation entityWithRelation) {
        entityWithRelation.setRelation(objectRelationBo
                .findOneByObjectTypeAndReferenceId(entityWithRelation.getObject(), entityWithRelation.getId()));
}

This was causing the exception in a random (or looks like) collection of other unrelated entity that was participating in the same transaction. I don't know the exact reason but adding @Transactional(propagation = Propagation.REQUIRES_NEW) fixes the problem

Maybe Hibernate doesn't like you to modify the entity by hand, but the field was a transient field...

score 0 · Answer 6 · answered Nov 30 '11 at 05:41

0

If you need the list to be persisted you might need to annotate your list with @OneToMany to be able to persist your entity.

answered Nov 30 '11 at 05:41

emt14

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You are right. I left out this annotation to shorten my example - probably a bad idea. – deamon Nov 30 '11 at 07:45

score -1 · Answer 7 · answered Jul 21 '12 at 04:12

-1

the problem is with your joining check whether you are not fatching any data which is not in the table

answered Jul 21 '12 at 04:12

sandeep pachauri

1

HibernateException: Found two representations of same collection

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