JFrame example.

JFrame.java

import javax.swing.JFrame;
import javax.swing.JPanel;

class Main {
	
	private static final String TITLE = "My Game";
	private static final int[] DIMENSIONS = {800, 600};
	
	public static void main(String s[]) {
		
		JFrame frame = new JFrame(TITLE);
		JPanel panel = new JPanel();
        
		panel.setLayout(null);
		
		frame.add(panel);
        frame.setSize(DIMENSIONS[0], DIMENSIONS[1]);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

    }

}