Подскажите для чего используется ActionCommand у элементов, как JRadioButton и JButton?

JRadioButton b = new JRadioButton;
b.setActionCommand("RadioB");

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
 
public class Main implements ActionListener {
 
   private JFrame mainForm;
 
   public Main() {
      mainForm = new JFrame("Main Form");
      mainForm.setSize(300, 75);
      mainForm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      mainForm.setLayout(new BorderLayout());
      mainForm.setVisible(true);
 
      JButton north = new JButton();
      north.setActionCommand("north");
      north.addActionListener(this);
      north.setText("north");
 
      JButton south = new JButton();
      south.setActionCommand("south");
      south.addActionListener(this);
      south.setText("south");
      mainForm.getContentPane().add(north, BorderLayout.NORTH);
      mainForm.getContentPane().add(south, BorderLayout.SOUTH);
   }
 
   @Override
   public void actionPerformed(ActionEvent actionEvent) {
      if (actionEvent.getActionCommand().equals("north")) {
         JOptionPane.showMessageDialog(mainForm,
               "Button " + ((JButton) actionEvent.getSource()).getText() + " clicked", "Info",
               JOptionPane.INFORMATION_MESSAGE);
      } else if (actionEvent.getActionCommand().equals("south")) {
         JOptionPane.showMessageDialog(mainForm,
               "Button " + ((JButton) actionEvent.getSource()).getText() + " clicked", "Info",
               JOptionPane.INFORMATION_MESSAGE);
      }
   }
 
   public static void main(String[] args) {
      new Main();
   }
}