If an exception occurs when an attempt is made to change an attribute, the text of the exception will be passed back to the user via the notification 'message'. The getMessage() method can thus be used to retrieve the exception text. The AttributeChangeNotification class also provides getOldValue() and getNewValue() methods to return the original attribute value and the value to which it is being changed. In the event of an error, getNewValue() will not return the actual attribute value (since the attempt to change the attribute has not succeeded) – in this case, getOldValue() returns the actual attribute value at the point of notification.