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.
As you noticed, the semi-colon is allowed but not necessary. I don't know why this is, maybe it was done to make life easier for C++ programmers switching to Java; in C++, the rules for semi-colons are slightly different.