Action.DISPLAYED_MNEMONIC_INDEX_KEY has the following syntax.
static final String DISPLAYED_MNEMONIC_INDEX_KEY
In the following code shows how to use Action.DISPLAYED_MNEMONIC_INDEX_KEY field.
import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.KeyEvent; // ww w. j a va2 s . c om import javax.swing.AbstractAction; import javax.swing.Action; import javax.swing.JCheckBox; import javax.swing.JFrame; import javax.swing.plaf.metal.MetalIconFactory; public class Main { public static void main(String[] a) { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Action action = new ShowAction(); JCheckBox button = new JCheckBox(action); frame.add(button, BorderLayout.CENTER); frame.setSize(350, 150); frame.setVisible(true); } } class ShowAction extends AbstractAction { public ShowAction() { super("About"); putValue(Action.MNEMONIC_KEY, new Integer(KeyEvent.VK_A)); putValue(Action.NAME, "Go to number "); putValue(Action.DISPLAYED_MNEMONIC_INDEX_KEY,1); } public void actionPerformed(ActionEvent actionEvent) { System.out.println("About Swing"); } }