Java;调整窗口大小后，paint（Graphics）调用过多！

    @Override
    public void paint(Graphics g) {
        createVolatileImage();

        do {
            GraphicsConfiguration gc = getGraphicsConfiguration();
            Graphics offscreenGraphics = volatileImage.getGraphics();

            int validationCode = volatileImage.validate(gc);
            if (validationCode == VolatileImage.IMAGE_INCOMPATIBLE) {
                createVolatileImage();
            }

            offscreenGraphics.setColor(getBackground());
            offscreenGraphics.fillRect(0, 0, getSize().width, getSize().height);

            offscreenGraphics.setColor(getForeground());
            paint(offscreenGraphics);

            g.drawImage(volatileImage, 0, 0, this);
        } while (volatileImage.contentsLost());
    }

    private void createVolatileImage() {
        GraphicsConfiguration gc = getGraphicsConfiguration();
        volatileImage = gc.createCompatibleVolatileImage(getWidth(), getHeight());
    }