Mnemonic, one character in a label appears underlined.
import java.awt.event.KeyEvent; import javax.swing.JButton; import javax.swing.JFrame; public class MnemonicButton { public static void main(String args[]) { JFrame frame = new JFrame("DefaultButton"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JButton button1 = new JButton("Text Button"); button1.setMnemonic(KeyEvent.VK_B); frame.add(button1); frame.setSize(300, 200); frame.setVisible(true); } }