learning java AWT Dialog

import java.awt.*;

public class DialogTest {
    Frame f = new Frame("test");
    Dialog d1 = new Dialog(f, "model dialog", true);
    Dialog d2 = new Dialog(f, "non-model dialog", false);
    Button b1 = new Button("open model dialog");
    Button b2 = new Button("open non-model dialog");
    public void init(){
        d1.setBounds(20,30,300,400);
        d2.setBounds(20,30,300,400);
        b1.addActionListener(e -> d1.setVisible(true));
        b2.addActionListener(e -> d2.setVisible(true));

        f.add(b1);
        f.add(b2,BorderLayout.SOUTH);
        f.pack();
        f.setVisible(true);

    }

    public static void main(String[] args) {
        new DialogTest().init();
    }


}