code: public static KeyManagerFactory keyManagerFactory(AbstractConfig config, String key) {
      final String keyManagerFactoryType = config.getString(key);
      try {
        return KeyManagerFactory.getInstance(keyManagerFactoryType);
      } catch (NoSuchAlgorithmException e) {
        ConfigException exception = new ConfigException(
            key,
            keyManagerFactoryType,
            "Unknown Algorithm."
        );
        exception.initCause(e);
        throw exception;
      }
    }
docs: Method will create a KeyManagerFactory based on the Algorithm type specified in the config.
  
  @param config Config to read from.
  @param key    Key to read from
  @return KeyManagerFactory based on the type specified in the config.