docs: public static File writeObjectToFile(Object o, File file, boolean append) throws IOException {
      // file.createNewFile(); // cdm may 2005: does nothing needed
      ObjectOutputStream oos = new ObjectOutputStream(new BufferedOutputStream(
          new GZIPOutputStream(new FileOutputStream(file, append))));
      oos.writeObject(o);
      oos.close();
      return file;
    }