private Response ActionDownloadSingleFile(InputStream fis)    {
    Response response = null;
    response = newChunkedResponse(Response.Status.OK, "application/octet-stream",fis);
    response.addHeader("Content-Disposition", "attachment; filename="+"my.zip");
    return response;
}

public static void zip(String[] files, String zipFile) throws IOException {
    BufferedInputStream origin = null;
    ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(zipFile)));
    try {
        byte data[] = new byte[BUFFER_SIZE];

        for (int i = 0; i < files.length; i++) {
            FileInputStream fi = new FileInputStream(files[i]);
            origin = new BufferedInputStream(fi, BUFFER_SIZE);
            try {
                ZipEntry entry = new ZipEntry(files[i].substring(files[i].lastIndexOf("/") + 1));
                out.putNextEntry(entry);
                int count;
                while ((count = origin.read(data, 0, BUFFER_SIZE)) != -1) {
                    out.write(data, 0, count);
                }
            }
            finally {
                origin.close();
            }
        }
    }
    finally {
        out.close();
    }
}

File file= new File("my.zip");
FileInputStream fis = null;
try
{
    fis = new FileInputStream(file);
} catch (FileNotFoundException ex)
{

}