package mipaquete;
  import javax.swing.*;
  public class Ventana {
    public static void main(String[] args) {
     JFrame ventana = new JFrame("");
     ventana.setAlwaysOnTop(true);
     ventana.setSize(300,300);
     ventana.setVisible(true);
     JDialog dialogo_Modal = new JDialog(ventana, "Dialogo Modal", true);
     dialogo_Modal.setSize(300,300);
     dialogo_Modal.setLocationRelativeTo(null);
     dialogo_Modal.setVisible(true);
   }
}