import javax.swing.*;
public class MDITest 
{
    public static void main(String[] argv)
    {
        JFrame frame = new JFrame("MDI Demo");
        JDesktopPane desk = new JDesktopPane();
        frame.getContentPane().add(desk);
        frame.setSize(300, 300);
        frame.setVisible(true);
        JInternalFrame doc =
            new JInternalFrame("Document 1", true, true, true);
        doc.setBounds(20, 20, 150, 100);
        desk.add(doc);
        doc.setVisible(true);
    }
}