code: private static void updateIndexWithSettingsInElasticsearch(RestClient client, String index, String settings) throws Exception {
  		logger.trace("updateIndex([{}])", index);
  
  		assert client != null;
  		assert index != null;
  
  
  		if (settings != null) {
  			logger.trace("Found update settings for index [{}]: [{}]", index, settings);
  			logger.debug("updating settings for index [{}]", index);
              Request request = new Request("PUT", "/" + index + "/_settings");
              request.setJsonEntity(settings);
  			client.performRequest(request);
  		}
  
  		logger.trace("/updateIndex([{}])", index);
  	}
docs: Update settings in Elasticsearch
  @param client Elasticsearch client
  @param index Index name
  @param settings Settings if any, null if no update settings
  @throws Exception if the elasticsearch API call is failing