code: public static long zip(File directory, File outputZipFile) throws IOException
    {
      return zip(directory, outputZipFile, false);
    }
docs: Zip the contents of directory into the file indicated by outputZipFile. Sub directories are skipped
  
  @param directory     The directory whose contents should be added to the zip in the output stream.
  @param outputZipFile The output file to write the zipped data to
  
  @return The number of bytes (uncompressed) read from the input directory.
  
  @throws IOException