import java.awt.Dimension;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;

class Test {
    public static void main (String[] args) {
        SwingUtilities.invokeLater (new Runnable () {

            public void run () {
                new Gui ();
            }

        });
    }
}

class Gui {
    JFrame f;

    public Gui () {
        f = new JFrame ();
        f.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
        f.setPreferredSize (new Dimension (100, 100));

        f.pack ();
        f.setVisible (true);
    }

    public boolean isVisible () {
        return f.isVisible ();
    }
}