Converting a Jpeg into an uncompressed tiff image

I found this code on StackOverflow

import java.io.File;
import java.io.FileOutputStream;
import java.awt.image.RenderedImage;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import javax.media.ja开发者_开发知识库i.NullOpImage;
import javax.media.jai.OpImage;
import com.sun.media.jai.codec.SeekableStream;
import com.sun.media.jai.codec.FileSeekableStream;
import com.sun.media.jai.codec.TIFFDecodeParam;
import com.sun.media.jai.codec.ImageDecoder;
import com.sun.media.jai.codec.ImageCodec;

public class Main {
    public static void main(String args[]) {
        File file = new File("input.tif");
        try {
            SeekableStream s = new FileSeekableStream(file);
            TIFFDecodeParam param = null;
            ImageDecoder dec = ImageCodec.createImageDecoder("tiff", s, param);
            RenderedImage op = new NullOpImage(dec.decodeAsRenderedImage(0),
                                               null,
                                               OpImage.OP_IO_BOUND,
                                               null);
            FileOutputStream fos = new FileOutputStream("output.jpg");
            JPEGImageEncoder jpeg = JPEGCodec.createJPEGEncoder(fos);
            jpeg.encode(op.getData());
            fos.close();
        }
        catch (java.io.IOException ioe) {
            System.out.println(ioe);
        } 
    }
}

I have been trying to reverse this process - convert jpg to uncompressed tiff but but I cant seem to get it to work.

Any ideas?