private static void pruneOutdated() {
    Path historyDir = getCommandHistoryDir();
    if (historyDir != null) {
      try (Stream<Path> s = Files.list(historyDir)) {
        getInstance().doPruneOutdated(s.collect(Collectors.toList()));
      }
      catch (IOException e) {
        LOG.warn("Cannot list files in " + historyDir, e);
      }
    }
  }
private static void pruneOutdated()