This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
In short, the getContentPane() allows you to get a hand on the JPanel instance contained in a JFrame. It is handy when you want to add components, because you can not add components directy to a JFrame instance. Anyway if you try to do it, you won't get any compilation error or warning (If anybody can tell me why, I would be pleased) but a runtime error: java.lang.Error: Do not use Toto.add() use Toto.getContentPane().add() instead if Toto is an instance of JFrame. W. W.