Graphics g = this.screen.getGraphics();
Graphics2D g2d = (Graphics2D)g;
Graphics appG = getGraphics();

g2d = (Graphics2D) screen.getGraphics();
      g2d.setColor(Color.white);
      g2d.fillRect(0, 0, screen.getWidth(), screen.getHeight());
      g2d.scale(3, 3);
      for (Entity e:this.entities){
         e.Draw(g2d);
      }
      g2d.setColor(Color.green);
      //g2d.fillRect(10, 10, 100, 50);
      appG.drawImage(screen, 0 , 0, screen.getWidth(),screen.getHeight(),null);

public class Game extends Canvas {
   public void render() {
      Graphics g = getGraphics();
      for (Entity e : entities) {
         e.Draw(g);
      }
   }

   public static void main(String[] args) {
      Game game = new Game();

      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.add(game);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

}