This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
You cannot turn an Observable into a String. The first parameter (Observable o) is the object that called notifyObservers. It is the second parameter (Object arg) that corresponds to the argument you provided when you called notifyObservers(Object arg).