private static void deleteTempFiles(Set<? extends File> tempFiles) {
    if (tempFiles != null) {
      try {
        for (File file : tempFiles) {
          FileUtil.delete(file);
        }
      }
      catch (Throwable t) {
        LOG.error("failed to delete temp. files", t);
      }
    }
  }
private static void deleteTempFiles(Set<? extends File> tempFiles)