code: public static void updateSettings(RestClient client, String root, String index) throws Exception {
  		String settings = IndexSettingsReader.readUpdateSettings(root, index);
  		updateIndexWithSettingsInElasticsearch(client, index, settings);
  	}
docs: Update index settings in Elasticsearch. Read also _update_settings.json if exists.
  @param client Elasticsearch client
  @param root dir within the classpath
  @param index Index name
  @throws Exception if the elasticsearch API call is failing