Hi, I am trying to compile this clases: Code: import java.util.ArrayList; import java.awt.*; class Test { public static void main(String[] args){ System.out.println("Prueba"); MyWindow win1 = new MyWindow ("ventana"); } } Code: import java.awt.*; import java.awt.event.*; class MyWindow extends Frame implements WindowListener { public MyWindow () { super(); } public MyWindow (String title) { super(title); setSize(500,500); addWindowListener(this); } public void windowActivated (WindowEvent e) {;} public void windowClosed (WindowEvent e) {;} public void windowClosing (WindowEvent e) {;System.exit(0);} public void windowDeactivated (WindowEvent e) {;} public void windowDeiconified (WindowEvent e) {;} public void windowIconified (WindowEvent e) {;} public void windowOpened (WindowEvent e) {;} } This is the error: Thanks!