docs: protected void initInstanceRevisionAndJanitor() throws Exception {
          databaseRevision = new DatabaseRevision();
  
          // Get the local file revision from disk (upgrade; see JCR-1087)
          long localFileRevision = 0L;
          if (getRevision() != null) {
              InstanceRevision currentFileRevision = new FileRevision(new File(getRevision()), true);
              localFileRevision = currentFileRevision.get();
              currentFileRevision.close();
          }
  
          // Now write the localFileRevision (or 0 if it does not exist) to the LOCAL_REVISIONS
          // table, but only if the LOCAL_REVISIONS table has no entry yet for this cluster node
          long localRevision = databaseRevision.init(localFileRevision);
          log.info("Initialized local revision to " + localRevision);
  
          // Start the clean-up thread if necessary.
          if (janitorEnabled) {
              janitorThread = new Thread(new RevisionTableJanitor(), "Jackrabbit-ClusterRevisionJanitor");
              janitorThread.setDaemon(true);
              janitorThread.start();
              log.info("Cluster revision janitor thread started; first run scheduled at " + janitorNextRun.getTime());
          } else {
              log.info("Cluster revision janitor thread not started");
          }
      }