public List<MetastoreTaskThread> getAlwaysTasks() throws Exception {
    List<MetastoreTaskThread> alwaysTasks = new ArrayList<>();
    Collection<String> taskNames =
        MetastoreConf.getStringCollection(configuration, MetastoreConf.ConfVars.TASK_THREADS_ALWAYS);
    for (String taskName : taskNames) {
      MetastoreTaskThread task =
          JavaUtils.newInstance(JavaUtils.getClass(taskName, MetastoreTaskThread.class));
      alwaysTasks.add(task);
    }
    return alwaysTasks;
  }
invoke setConf(Configuration conf) before running
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/leader/HouseKeepingTasks.java