Java by API/java.awt.event/ActionListener

implements ActionListener

   <source lang="java">

import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class MainClass extends JPanel {

 public MainClass() {
   JButton btn1 = new JButton("Button1");
   btn1.addActionListener(new ButtonListener());
   add(btn1);
 }
 public static void main(String[] args) {
   JFrame frame = new JFrame();
   frame.getContentPane().add(new MainClass());
   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   frame.setSize(200, 200);
   frame.setVisible(true);
 }

} class ButtonListener implements ActionListener {

 ButtonListener() {
 }
 public void actionPerformed(ActionEvent e) {
   if (e.getActionCommand().equals("Button1")) {
     System.out.println("Button1 has been clicked");
   }
 }

}

      </source>