java - 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?

Answer 1

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.