||This abstract class is a partial implementation of the abstract class
Preferences, which can be used to simplify
||This is the event class to indicate that one child of the preference node has
been added or deleted.
||This is the event class to indicate that a preference has been added, deleted
||An instance of the class
Preferences represents one node in a
preference tree, which provides a mechanism to store and access configuration
data in a hierarchical way.