Set newAttributes = new PropertyListSet();
Set newAttributes = new HashSet();
  public void removeAttribute(EOAttribute _attribute, boolean _removeFromSubclasses) {    String attributeName = _attribute.getName();    Set oldAttributes = myAttributes;    Set newAttributes = new PropertyListSet();    newAttributes.addAll(myAttributes);    newAttributes.remove(_attribute);    myAttributes = newAttributes;    firePropertyChange(EOEntity.ATTRIBUTES, oldAttributes, newAttributes);    if (_removeFromSubclasses) {      Iterator childrenEntitiesIter = getChildrenEntities().iterator();      while (childrenEntitiesIter.hasNext()) {        EOEntity childEntity = (EOEntity) childrenEntitiesIter.next();        EOAttribute childAttribute = childEntity.getAttributeNamed(attributeName);        if (childAttribute != null) {          childEntity.removeAttribute(childAttribute, _removeFromSubclasses);        }      }    }    _attribute._setEntity(null);  }