code: public static ApiOvhCore getInstance() {
  		ApiOvhCore core = new ApiOvhCore();
  		// core._consumerKey = core.config.getConsumerKey();
  		core._consumerKey = core.getConsumerKeyOrNull();// config.getConsumerKey();
  		if (core._consumerKey == null) {
  			File file = ApiOvhConfigBasic.getOvhConfig();
  			String location = ApiOvhConfigBasic.configFiles;
  			if (file != null)
  				location = file.getAbsolutePath();
  			String url = "";
  			String CK = "";
  			try {
  				OvhCredential credential = core.requestToken(null);
  				url = credential.validationUrl;
  				CK = credential.consumerKey;
  			} catch (Exception e) {
  				log.error("Fail to request a new Credential", e);
  			}
  			log.error("activate the CK {} here: {}", CK, url);
  			throw new NullPointerException("no 'consumer_key' present in " + location
  					+ " or environement 'OVH_CONSUMER_KEY', activate the CK '" + CK + "' here: " + url);
  		}
  		return core;
  	}
docs: Connect to the OVH API using a consumerKey contains in your ovh config file
  or environment variable
  
  @return an ApiOvhCore authenticate by consumerKey