Set newRelationships = new PropertyListSet();
Set newRelationships = new HashSet();
  public void removeRelationship(EORelationship _relationship, boolean _removeFromSubclasses) {    String relationshipName = _relationship.getName();    Set oldRelationships = myRelationships;    Set newRelationships = new PropertyListSet();    newRelationships.addAll(myRelationships);    newRelationships.remove(_relationship);    myRelationships = newRelationships;    firePropertyChange(EOEntity.RELATIONSHIPS, oldRelationships, newRelationships);    if (_removeFromSubclasses) {      Iterator childrenEntitiesIter = getChildrenEntities().iterator();      while (childrenEntitiesIter.hasNext()) {        EOEntity childEntity = (EOEntity) childrenEntitiesIter.next();        EORelationship childRelationship = childEntity.getRelationshipNamed(relationshipName);        if (childRelationship != null) {          childEntity.removeRelationship(childRelationship, _removeFromSubclasses);        }      }    }    _relationship._setEntity(null);  }