Java JFrame渲染滞后

Question

我试图使用swing引擎在java中制作一个简单的游戏。但是目前我遇到滞后问题。这个简单的代码绘制一个圆圈并将其从框架的左上角移动到右下角，但它滞后很多。虽然我的电脑有点陈旧，i3 4gb内存，我认为应该设法执行此操作而不会滞后？

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.Timer;

public class Game extends JPanel implements ActionListener {

  public Timer timer;
  int x = 0;
  int y = 0;

  public Game() {
    timer = new Timer(20, this);
    timer.start();
  }

  @Override
  public void paint(Graphics g) {
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.fillOval(x, y, 15, 15);
  }

  public void actionPerformed(ActionEvent e) {
    x++;
    y++;
    repaint();
  }

  public static void main(String[] args) throws InterruptedException {
    JFrame frame = new JFrame("test");
    Game game = new Game();
    frame.add(game);
    frame.setSize(600, 600);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

   }
}