This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
I suspect this example came from the book "Struts in Action". The UserDirectory class is one that the book directs you to write and the book provides the code for it. It is not one of the standard Struts classes.