codigo

import java.awt.*;
import java.awt.event.*;

@SuppressWarnings("serial")
public class Ejvent extends Frame implements WindowListener , ActionListener , KeyListener{
        Button b1,b2;
        Label lb1,lb2;
        List l1;
        Choice ch1;
        TextField tf1,tf2;

        public Ejvent(){
                setLayout(null);
                setTitle("Ejemplo Ventana 1");


                l1=new List(4,true);
                l1.setBounds(20,200,100,100);
                l1.add("Audi");
                l1.add("BMW");
                l1.add("Chevrolet");
                l1.add("Mercedez Benz");
                l1.add("Toyota");
                add(l1);

                ch1=new Choice();
                ch1.setBounds(150,200,130,15);
                ch1.add("Audi");
                ch1.add("BMW");
                ch1.add("Chevrolet");
                ch1.add("Mercedes benz");
                ch1.add("Toyota");
                add(ch1);

                lb1=new Label("Codigo:");
                lb1.setBounds(20,50,100,20);
                add(lb1);

                lb2=new Label();
                lb2.setBounds(250,350,100,20);
                add(lb2);

                tf1=new TextField();
                tf1.setBounds(125,50,50,20);
                add(tf1);


                tf2=new TextField();
                tf2.setBounds(250,300,100,20);
                add(tf2);


                b1=new Button("Salir");
                b1.setBounds(250,150,100,40);
                add(b1);

                b2=new Button("Mostrar");
                b2.setBounds(100,150,100,40);
                add(b2);

                b1.addActionListener(this);
                b2.addActionListener(this);
                addWindowListener(this);
                tf1.addKeyListener(this);

}

        public static void main(String[] args) {
                Ejvent ev = new Ejvent();
                ev.setSize(500,400);
                ev.setVisible(true);
                ev.setLocationRelativeTo(null);

}

        public void windowOpened(WindowEvent e) {

}


        public void windowClosing(WindowEvent e) {
                System.exit(0);
}


        public void windowClosed(WindowEvent e) {

}


        public void windowIconified(WindowEvent e) {

}


        public void windowDeiconified(WindowEvent e) {

}


        public void windowActivated(WindowEvent e) {

}


        public void windowDeactivated(WindowEvent e) {

 }


        public void actionPerformed(ActionEvent ae) {
                if (ae.getSource()==b2){
                        String s = tf1.getText();
                        tf2.setText(s);
                        lb2.setText(s);

                }
                if (ae.getSource()==b1){
                        System.exit(0);
                }

        }


        public void keyPressed(KeyEvent arg0) {

        }


        public void keyReleased(KeyEvent arg0) {

        }


        public void keyTyped(KeyEvent e) {
                if (tf1.getText().length()==4) {
                        e.consume();
                }
                char c = e.getKeyChar();
                if (!(Character.isDigit(c) ||
                (c == KeyEvent.VK_BACK_SPACE) ||
                (c == KeyEvent.VK_DELETE))) {
                getToolkit().beep();
                e.consume();
                }
                }
                ;


        }