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.
If by "retrieve" you mean parsing an XML file, then most likely you don't need to download anything. An XML parser and its supporting API classes are built into the JDK. Have a look at the javax.xml.parsers package.