Action.ACTION_COMMAND_KEY has the following syntax.
static final String ACTION_COMMAND_KEY
In the following code shows how to use Action.ACTION_COMMAND_KEY field.
import java.awt.BorderLayout; import java.awt.event.ActionEvent; /*w w w. j a v a 2 s . c o m*/ 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.ACTION_COMMAND_KEY, "command"); putValue(Action.NAME, "Go to number "); } public void actionPerformed(ActionEvent actionEvent) { System.out.println("About Swing"); } }