图片Exif信息修改代码编译时报错

import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import com.drew.imaging.ImageProcessingException;
import com.drew .imaging .jpeg.JpegMetadataReader;
import com.drew.metadata .Directory;
import com.drew .metadata.Metadata;
import com.drew.metadata .Tag;
import com.drew.metadata.exif.*;
import mediautil.image.jpeg.*;
import java.io.FileOutputStream;
public static void main(String[] args) throws Exception
{
LLJTran llj = new LLJTran(new File("E:\2012_07_17\IMG_0665.JPG"));

       // readImage(llj, true, LLJTran.READ_INFO, 0, 0);
        llj.read(LLJTran.READ_INFO,true);
        mediautil.image.jpeg.Exif  exifq=(Exif)llj.getImageInfo();
        Entry entry = exifq.getTagValue(Exif.USERCOMMENT, true);
        entry.setValue(0,"xxxxxxxxxxx");
        llj.refreshAppx();
        FileOutputStream nhop = new      FileOutputStream("E:\\2012_07_17\\IMG_0665.JPG");
        llj.xferInfo(null, nhop, LLJTran.REPLACE, LLJTran.REPLACE);
        nhop.close();

}
总是报这个错。mediautil.image.jpeg.JPEG cannot be cast to mediautil.image.jpeg.Exif

去看下官方的示例 有些图片没有Exif头 需要虚拟一个Exif头
// 3. If the Image does not have an Exif Header create a dummy Exif
// Header
if(!(imageInfo instanceof Exif))
{
System.out.println("Adding a Dummy Exif Header");
llj.addAppx(LLJTran.dummyExifHeader, 0,
LLJTran.dummyExifHeader.length, true);
imageInfo = llj.getImageInfo(); // This would have changed

        Exif exif = (Exif) imageInfo;

        // Changed Date/Time and dimensions in Dummy Exif
        Entry entry = exif.getTagValue(Exif.DATETIME, true);
        if(entry != null)
            entry.setValue(0, "1998:08:18 11:15:00");
        entry = exif.getTagValue(Exif.DATETIMEORIGINAL, true);
        if(entry != null)
            entry.setValue(0, "1998:08:18 11:15:00");
        entry = exif.getTagValue(Exif.DATETIMEDIGITIZED, true);
        if(entry != null)
            entry.setValue(0, "1998:08:18 11:15:00");

        int imageWidth = llj.getWidth();
        int imageHeight = llj.getHeight();
        if(imageWidth > 0 && imageHeight > 0)
        {
            entry = exif.getTagValue(Exif.EXIFIMAGEWIDTH, true);
            if(entry != null)
                entry.setValue(0, new Integer(imageWidth));
            entry = exif.getTagValue(Exif.EXIFIMAGELENGTH, true);
            if(entry != null)
                entry.setValue(0, new Integer(imageHeight));
        }
    }

附上链接 main3方法

表示一样问题，现在还没解决.
Exception in thread "main" java.lang.ClassCastException: mediautil.image.jpeg.JPEG