code: protected void log(String message, Writer writer) {
          try {
              writer.write(JournalHelper.formatDate(new Date()) + ": " + message
                      + "\n");
          } catch (IOException e) {
              logger.error("Error writing journal log entry", e);
          }
      }
docs: Concrete sub-classes call this method to perform the final formatting if
  a log entry.