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.
Find your Java installation folder and explore it until you find a file called "src.zip". Unzip it into a folder called src, then explore to find the java folder then the util folder then the ArrayList file then read the toString() method.