PDF转PNG时控制台刷一串ScratchFileBuffer not closed!!!如何解决?

图片最后能生成,但是 控制台刷了一串ScratchFileBuffer not closed! - 2019-04-13 22:03:49,204 DEBUG Finalizer

public static byte[] createPNG(byte[] by) {
        byte[] imgby=null;
        PDDocument doc =null;
        ByteArrayOutputStream baos = null;
        PDFRenderer renderer =null;

        try {
            baos = new ByteArrayOutputStream();
            doc = PDDocument.load(by);
            renderer = new PDFRenderer(doc);
            int pageCount = doc.getNumberOfPages();
            for (int i = 0; i < pageCount; i++) {
                //BufferedImage image = renderer.renderImageWithDPI(i, 296);

                BufferedImage image = renderer.renderImage(i, 2.5f);
                ImageIO.write(image, "PNG", baos);

                //imgby = baos.toByteArray();
                //baos.close();
                image.flush();

            }
            imgby = baos.toByteArray();

        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                baos.flush();
                baos.close();
                doc.close();

            } catch (IOException e) {
                System.out.println("关闭流异常");
                e.printStackTrace();
            }
        }
        // buff2Image(by,"d:\\logs\\test.jpg");
        System.out.println("over"+":"+imgby.length);
        return imgby;
    }

在配置文件中设置日志级别为info，或者在main方法中修改日志级别。