code: @Override
      protected synchronized JournalInputFile openNextFile()
              throws JournalException {
          while (open) {
              JournalInputFile nextFile = super.openNextFile();
              if (nextFile != null) {
                  return nextFile;
              }
              try {
                  wait(pollingIntervalMillis);
              } catch (InterruptedException e) {
                  // no special action on interrupt.
              }
          }
          return null;
      }
docs: Ask for a new file, using the superclass method, but if none is found,
  wait for a while and ask again. This will continue until we get a server
  shutdown signal.