This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Remember, overridding methods can always be less restrictive than their parent methods. The one exception are private methods, which of course can't be overridden because they can't be seen by the subclass.