import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class Snippet
{

    public static void main(String[] args)
    {
        Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setSize(400, 300);
        final Shell s = new Shell(shell);
        s.setSize(100, 100);
        s.open();
        Thread t = new Thread(new Runnable()
        {

            @Override
            public void run()
            {
                Display.getDefault().asyncExec(new Runnable()
                {

                    @Override
                    public void run()
                    {
                        boolean openQuestion = MessageDialog.openQuestion(s, "", "Yes Or No");

                        System.out.println(openQuestion);
                    }
                });

            }
        });
        t.start();
        Thread t1 = new Thread(new Runnable()
        {

            @Override
            public void run()
            {
                Display.getDefault().asyncExec(new Runnable()
                {

                    @Override
                    public void run()
                    {
                        s.dispose();
                    }
                });

            }
        });
        t1.start();

        shell.open();
        while (!shell.isDisposed())
        {
            if (!display.readAndDispatch()) display.sleep();
        }
        display.dispose();
    }
}