private MetaStoreFilterHook loadFilterHooks() throws IllegalStateException  {
    String errorMsg = "Unable to load filter hook at HMS server. ";

    String filterHookClassName = MetastoreConf.getVar(conf, ConfVars.FILTER_HOOK);
    Preconditions.checkState(!isBlank(filterHookClassName));

    try {
      return (MetaStoreFilterHook)Class.forName(
          filterHookClassName.trim(), true, JavaUtils.getClassLoader()).getConstructor(
          Configuration.class).newInstance(conf);
    } catch (Exception e) {
      LOG.error(errorMsg, e);
      throw new IllegalStateException(errorMsg + e.getMessage(), e);
    }
  }
Filter is actually enabled only when the configured filter hook is configured, not default, and
enabled in configuration
@return
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/HMSHandler.java