Access a preference. Returns the previously set value or
null if no such preference has been set.
Parameters: prefName - preference name. the value of the preference or null. throws: RemoteException - if a system-level error occurs. See Also:UserPrefsService.setPreference
Set a preference. Note that objects passed as values for preferences
must be serializable.
Parameters: prefName - preference name. Parameters: prefValue - preference value. throws: RemoteException - if a system-level error occurs. See Also:UserPrefsService.getPreference