String message="presses-donc";
Button presse1 = new Button ("oui");                                        // création d'un objet "bouton"
Button presse2 = new Button ("non");
public void init()  {

add (presse1);                                                                // mise en  place des boutons
add (presse2);
presse1.addActionListener(this);
presse1.setActionCommand("oui");
presse2.addActionListener(this);
presse2.setActionCommand("non");

}
public void actionPerformed(ActionEvent evt)    {                // gestion des événements "bouton"
             if (evt.getActionCommand().equals("oui"))
                           message=" tu as pressé le oui";
             else
                          message=" tu as pressé le non";
            repaint();
}
public void paint(Graphics g) {
             g.drawString(message,10,150);
}

}

mise en place de boutons

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

public class Bouton2 extends Applet implements ActionListener {
      private Label etiquette1 = null;
      private Button Bouton1 = null;
     private Button Bouton3 = null;
     String message= "presse sur un bouton";
    public Bouton2 (){
        super();
    }
    private java.awt.Label getetiquette1() {
        if (etiquette1 == null) {
            etiquette1 = new Label();
            etiquette1.setName("Texte 1");
            etiquette1.setText("Test boutons");
            etiquette1.setBounds(10, 10, 100, 20);
            etiquette1.setAlignment(Label.LEFT);
        }
        return etiquette1;
    }
    private Button getBouton1() {
        if (Bouton1 == null) {
            Bouton1 = new Button();
            Bouton1.setName("Bouton1");
            Bouton1.setLabel("droite");
            Bouton1.setBounds(65, 170, 55, 20);
            }
            return Bouton1;
        }
        private Button getBouton3() {
        if (Bouton3 == null) {
            Bouton3 = new Button();
            Bouton3.setName("Bouton3");
            Bouton3.setLabel("gauche");
            Bouton3.setBounds(1, 170, 55, 20);
            }
            return Bouton3;
        }            
    public void init(){
        super.init();
        this.setName("Texte 4");
        this.setLayout(null);
        this.setSize(128, 200);
        this.add(this.getetiquette1(), this.getetiquette1().getName());
        this.add(this.getBouton1(), this.getBouton1().getName());
       this.getBouton1().addActionListener(this);
        this.add(this.getBouton3(), this.getBouton3().getName());
        this.getBouton3().addActionListener(this);
    }
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == this.getBouton1())
                                    message =" bouton de droite";
        else
                message="bouton de gauche";
        repaint();
    }
    public void paint (Graphics g) {
        g.drawString ( message, 10,50);
    }
}