This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Somewhere in your Java installation folder you will find a file called src.zip. Unzip that, then navigate to its "java" folder, then its "lang" folder. You will notice the folder structure follows the package name structure.