code: public static boolean isSensitive(String key) {
  		Preconditions.checkNotNull(key, "key is null");
  		final String keyInLower = key.toLowerCase();
  		for (String hideKey : SENSITIVE_KEYS) {
  			if (keyInLower.length() >= hideKey.length()
  				&& keyInLower.contains(hideKey)) {
  				return true;
  			}
  		}
  		return false;
  	}
docs: Check whether the key is a hidden key.
  
  @param key the config key