Java Action SELECTED_KEY

static final String SELECTED_KEY

/* w  w w. j ava 2 s  .  c  om*/
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JCheckBox;
import javax.swing.JFrame;

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.SELECTED_KEY,true);
    
  }

  public void actionPerformed(ActionEvent actionEvent) {
    System.out.println("About Swing");
  }
}