Апплети

import java.awt.*;
import java.applet.*;
public class My_Applet extends Applet{
public void paint(Graphics g){
g.drawString("Hello, World!", 5, 30);
}
}

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.applet.*;

public class My_Applet extends Applet{

public void init(){

setLayout(null);

final TextField tf1 = new TextField(15);

tf1.setBounds(1, 1, 100, 20);

add(tf1);

final TextField tf2 = new TextField(15);

tf2.setBounds(1, 25, 100, 20);

add(tf2);

final TextField tf3 = new TextField(15);

tf3.setBounds(1, 50, 100, 20);

add(tf3);

Button b1 = new Button("Кнопка 1");

b1.setBounds(1, 100, 100, 20);

add(b1);

b1.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent event){

try{

tf3.setText(String.valueOf((Long.valueOf(tf1.getText())

+Long.valueOf(tf2.getText()))));

 }catch(Exception e){

 tf3.setText("Введите числа");

 }

 }

 });

}

}