code: public static void addCacheArchive(URI uri, Configuration conf) {
      String archives = conf.get("mapred.cache.archives");
      conf.set("mapred.cache.archives", archives == null ? uri.toString()
               : archives + "," + uri.toString());
    }
docs: Add a archives to be localized to the conf
  @param uri The uri of the cache to be localized
  @param conf Configuration to add the cache to