A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance : Solved
This usually happen when the child entities are not referred by the parent entities. This might happen if you are setting a new object using the setter method of this child entity. For Example : parent.setChildrens(new ArrayList<?>); // This create the problem because in this case the parent won't find any reference to the original entity. Solution : parent.getChildrens().clear(); parent.getChildrens().addAll( collection) This will solve the problem