1 import javax.swing.*; 2 import java.awt.event.*; 3  4 class Gui implements ActionListener{ 5      6     JButton button = new JButton("click me"); 7  8     public void show() { 9         JFrame frame = new JFrame();10         11         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);12         13         frame.getContentPane().add(button);14         frame.setSize(300, 200);15         frame.setVisible(true);16         17         button.addActionListener(this);18     }19     20     public void actionPerformed( ActionEvent event ) {21         button.setText("I‘ve been clicked!");22     }23 }24 25 class GuiTest {26     public static void main( String[] args ) {27         Gui gui = new Gui();28         gui.show();29     }30 }