@Override
  public void run() {
    while (true) {
      try {
        doOneCleanupRound();
      } catch (InterruptedException ex) {
        LlapIoImpl.LOG.warn("Cleanup thread has been interrupted");
        Thread.currentThread().interrupt();
        break;
      } catch (Throwable t) {
        LlapIoImpl.LOG.error("Cleanup has failed; the thread will now exit", t);
        break;
      }
    }
  }
Class used to slowly clean up a map of FileCache-s.
llap-server/src/java/org/apache/hadoop/hive/llap/cache/FileCacheCleanupThread.java