Hibernate TransientObjectException on OneToMany with CascadeType.ALL if we call iterator() before save

Question

I have OneToMany Relation in hibernate like below:

class Container {
    @OneToMany( cascade = {CascadeType.ALL}, mappedBy = "container", orphanRemoval = true)
    List<Item> items;
}

the simplified scenario is that I load a Container object (container) from the database and try to add an Item to container.items like this:

Container container = entityManager.find(Container.class,id);
container.getItems().add(new Item(container));
entityManager.merge(container);

and everything goes fine. But in my case, I want to iterate over items and check something, but when I just call container.getItems().iterator and save container like this:

Container container = entityManager.find(Container.class,id);
container.getItems().add(new Item(container));
container.getItems().iterator(); // here is the change
entityManager.merge(container); // here is where exception occured

I get the following error

org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance beforeQuery flushing: mypackage.items

I have no idea why this exception occurs.

What happens if you `persist()` the new item before adding to the list? — yegodm, Jan 10 '18 at 10:02
@yegodm it works but what was wrong about `iterator()`, I want to use it to remove duplicates from the items. — Hossein Nasr, Jan 10 '18 at 12:54
What is your version of Hibernate? I cannot reproduce the case with 5.2.12. — yegodm, Jan 17 '18 at 12:08
Can't reproduce with 5.2,4 either. What's your `Item` mapping? — yegodm, Jan 19 '18 at 09:29
what do you mean by "`Item` mapping"? ```@Id @GeneratedValue(strategy = GenerationType.IDENTITY) Long id; @ManyToOne(optional = false) Container container; @ManyToOne(optional = false) Tag tag;``` — Hossein Nasr, Jan 21 '18 at 14:30
Dunno, whatever I try works fine. What is the database you are using? — yegodm, Jan 22 '18 at 14:48

score 2 · Answer 1 · answered Jan 08 '18 at 14:12

2

Your item object needs to have a reference to its parent:

Container container = entityManager.find(Container.class,id);
Item item = new Item();
item.setContainer(container); //needed
container.getItems().add(item);

answered Jan 08 '18 at 14:12

Wilder Valera

986
9
11

Unfortunately, I did that. But since I simplified my code, I removed it. the interesting thing is that the problem occurs only when I call `iterator()`. Otherwise, everything is fine. – Hossein Nasr Jan 10 '18 at 08:51
This exception occurs when trying to use the Domain property with the data model having detached state. You need to explicitly fetch the Domain Object using the property and use this fetched object further using session.load(yourTransientObject) – Praveen Shendge Aug 08 '18 at 15:05

Hibernate TransientObjectException on OneToMany with CascadeType.ALL if we call iterator() before save

1 Answers1