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.
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: