重复重绘BufferedImage时防止水平线/半帧

Question

我有一个显示动画的swing组件。动画帧是动态计算的（在BufferedImage中）并以大约30fps的速度显示。

问题在于，它偶尔会产生半帧 - 在输出中给出非常明显的不连续性（在下面给出的测试用例中应该只是闪烁黑/白）。

谁能告诉我导致故障的原因以及如何解决这个问题？

请注意，运行此代码会产生快速闪烁的光线

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import javax.swing.JComponent;
import javax.swing.JFrame;

class Animation extends JComponent {
    FrameSource framesource;
    public Animation(FrameSource fs)
    {
        this.framesource = fs;
        setDoubleBuffered(true); 
        new Thread(new Runnable() {
            public void run() {
                while (true) {
                    framesource.computeNextFrame();
                    Animation.this.repaint();
                    try {Thread.sleep(30);} catch (InterruptedException e) {}
                }
            }
        }).start();
    }
    public Dimension getPreferredSize() {return new Dimension(500,500);}
    public void paintComponent(Graphics g) {
            g.drawImage(framesource.getCurrentFrame(), 0,0,null);
    }
}
class FrameSource
{
    private BufferedImage currentframe;
    public BufferedImage getCurrentFrame() {return currentframe;}
    int frameCount = 0;
    public void computeNextFrame()
    {
        BufferedImage nextFrame = new BufferedImage(500,500,BufferedImage.TYPE_INT_RGB);
        for (int x=0;x<500;x++)
            for (int y=0;y<500;y++)
            {
                nextFrame.setRGB(x, y, (frameCount%2==0)?16777215:0);
            }
        frameCount++;
        currentframe = nextFrame;
    }
}
public class Flickertest {
        public static void main(String[] args) 
        {
            JFrame frame = new JFrame();
            FrameSource fs = new FrameSource();
            Animation a = new Animation(fs);
            frame.getContentPane().add(a);
            frame.pack();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        }
}