private List<Thread> createOldWalsCleaner(int size) {
    LOG.info("Creating {} old WALs cleaner threads", size);

    List<Thread> oldWALsCleaner = new ArrayList<>(size);
    for (int i = 0; i < size; i++) {
      Thread cleaner = new Thread(() -> deleteFile());
      cleaner.setName("OldWALsCleaner-" + i);
      cleaner.setDaemon(true);
      cleaner.start();
      oldWALsCleaner.add(cleaner);
    }
    return oldWALsCleaner;
  }
@param period    the period of time to sleep between each run
@param stopper   the stopper
@param conf      configuration to use
@param fs        handle to the FS
@param oldLogDir the path to the archived logs
@param pool      the thread pool used to scan directories
hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/LogCleaner.java