import javax.swing.JFrame;
import javax.swing.JRootPane;
public class MainClass {
public static void main(final String args[]) {
JFrame frame = new JFrame("Adornment Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setUndecorated(true);
frame.getRootPane().setWindowDecorationStyle(JRootPane.FRAME);
frame.setSize(300, 100);
frame.setVisible(true);
}
}