import javax.swing.SwingUtilities;

public class Window {
	
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		SwingUtilities.invokeLater(new Runnable(){

			@Override
			public void run() {
				// TODO Auto-generated method stub
				
			}
		});

	}
	
	public Window(){

	}
} 

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

public class Window extends JPanel{
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		SwingUtilities.invokeLater(new Runnable(){
			
			@Override
			public void run() {
				JFrame restaurantFrame = new JFrame("restaurant");
				restaurantFrame.setSize(800,800);
				restaurantFrame.setResizable(false);
				restaurantFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				restaurantFrame.add(new Window());
				restaurantFrame.setVisible(true);		
			}
		});

	}
	
	public Window(){
		
	}
	
	
} 

add frame