In addition to regular data, Group, Element, and Att objects can contain metadata. Applications can, and Info*Engine itself does, use metadata to register information about an object on the object itself. Each metadata item is a name/value pair. Most metadata items created and used by Info*Engine have names beginning with com.infoengine. Applications can add their own metadata items, but they should avoid using names that begin with com.infoengine because this namespace is reserved by Info*Engine. All of the information classes provide methods that support inspection, creation, and management of metadata. For details on these methods, see the Javadoc.