import java.awt.Window;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame(Main.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JButton button = new JButton("Click me to open dialog");
button.addActionListener(e -> {
Window parentWindow = SwingUtilities.windowForComponent(button);
JDialog dialog = new JDialog(parentWindow);
dialog.setLocationRelativeTo(button);
dialog.setModal(true);
dialog.add(new JLabel("A dialog"));
dialog.pack();
dialog.setVisible(true);
});
frame.add(button);
frame.pack();
frame.setVisible(true);
}
}