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.
Related to your doubt about the exceptions, the overriden method can throw any exception that is subclass of the exception which is thrown by the base class method and also it might throw any RuntimeException. As ArithmeticException is subclass of RuntimeException the overriden method can throw arithmetic exception.