This week's book giveaways are in the Refactoring and Agile forums. We're giving away four copies each of Re-engineering Legacy Software and Docker in Action and have the authors on-line! See this thread and this one for details.
Try checking the API: javax.swing.JButton. You search for something like "background". You find nothing declared by JButton itself, but wait! there is a method called setBackground in JComponent. And lo and behold: