HibernateException: Found two representations of same collection
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.
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);
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>();