From Joomla! Documentation
The "API15" namespace is an archived namespace. This page contains information for a Joomla! version which is no longer supported. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.
JApplicationHelper is a class which provides helper functions for using JApplication. JApplicationHelper has functions to help you get client information, paths, and parse XML files into associative arrays.
|getClientInfo||Gets information on a specific client id. This method will be useful in future versions when we start mapping applications in the database.|
|getPath||Get a path|
jimport( 'joomla.application.helper' );