@Override
    protected HiveMetastoreAuthenticationProvider initialValue() {
      try {
        return (HiveMetastoreAuthenticationProvider) HiveUtils.getAuthenticator(tConfig.get(), HiveConf.ConfVars.HIVE_METASTORE_AUTHENTICATOR_MANAGER);
      } catch (HiveException excp) {
        throw new IllegalStateException("Authentication provider instantiation failure", excp);
      }
    }
HiveMetaStoreAuthorizer :  Do authorization checks on MetaStore Events in MetaStorePreEventListener
ql/src/java/org/apache/hadoop/hive/ql/security/authorization/plugin/metastore/HiveMetaStoreAuthorizer.java