Fullscreen Example

import java.awt.*;
import javax.swing.JFrame;
public class Test{
    public static void main(String[] args) {
        GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice device = env.getDefaultScreenDevice();

        JFrame myFrame = new JFrame("Title");
        myFrame.setUndecorated(true);
        myFrame.setResizable(false);
        myFrame.setSize(600,600);
        myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        device.setFullScreenWindow(myFrame);

        sleep(1000);

        device.setFullScreenWindow(null);

        myFrame.dispose();
        myFrame.setUndecorated(false);
        myFrame.setVisible(true);

        sleep(5000);

        myFrame.dispose();
        System.exit(0);
    }

    public static void sleep(long millis) {
        try{
            Thread.sleep(millis);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}