code: private void upgradeIfNeeded(File oldPidGenDir) throws IOException {
          if (oldPidGenDir != null && oldPidGenDir.isDirectory()) {
              String[] names = oldPidGenDir.list();
              Arrays.sort(names);
              if (names.length > 0) {
                  BufferedReader in =
                          new BufferedReader(new InputStreamReader(new FileInputStream(new File(oldPidGenDir,
                                                                                                names[names.length - 1]))));
                  String lastLine = null;
                  String line;
                  while ((line = in.readLine()) != null) {
                      lastLine = line;
                  }
                  in.close();
                  if (lastLine != null) {
                      String[] parts = lastLine.split("|");
                      if (parts.length == 2) {
                          neverGeneratePID(parts[0]);
                      }
                  }
              }
          }
      }
docs: Read the highest value from the old pidGen directory if it exists, and
  ensure it is never used.