Java tutorial
import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JRootPane; public class SettingDefaultButton { public static void main(String args[]) { JFrame frame = new JFrame("DefaultButton"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JButton button4 = new JButton("AAA"); frame.add(button4, "Center"); frame.add(new JButton("BBB"), "South"); JRootPane rootPane = frame.getRootPane(); rootPane.setDefaultButton(button4); frame.setSize(300, 200); frame.setVisible(true); } }