static AuthenticationProviderSelector instantiateSelector(Configuration conf,
    Collection<SaslClientAuthenticationProvider> providers) {
    Class<? extends AuthenticationProviderSelector> clz = conf.getClass(SELECTOR_KEY,
      BuiltInProviderSelector.class, AuthenticationProviderSelector.class);
    try {
      AuthenticationProviderSelector selector = clz.getConstructor().newInstance();
      selector.configure(conf, providers);
      if (LOG.isTraceEnabled()) {
        LOG.trace("Loaded ProviderSelector {}", selector.getClass());
      }
      return selector;
    } catch (InstantiationException | IllegalAccessException | NoSuchMethodException
      | InvocationTargetException e) {
      throw new RuntimeException(
        "Failed to instantiate " + clz + " as the ProviderSelector defined by " + SELECTOR_KEY, e);
    }
  }
Instantiates the ProviderSelector implementation from the provided configuration.
hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/SaslClientAuthenticationProviders.java