Java Code:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class NoButtonPopup {
  public static void main(String args[]) {

    JFrame frame = new JFrame("NoButton Popup");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JButton button = new JButton("Ask");
    ActionListener actionListener = new ActionListener() {
      public void actionPerformed(ActionEvent actionEvent) {
        Component source = (Component) actionEvent.getSource();
        int response = JOptionPane.showOptionDialog(source, "",
            "Empty?", JOptionPane.DEFAULT_OPTION,
            JOptionPane.QUESTION_MESSAGE, null, new Object[] {},
            null);
        System.out.println("Response: " + response);
      }
    };
    button.addActionListener(actionListener);
    Container contentPane = frame.getContentPane();
    contentPane.add(button, BorderLayout.SOUTH);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}