code: @Override
    public synchronized JobSpec getJobSpec(URI uri)
        throws JobSpecNotFoundException {
      try {
        Path targetJobSpecFullPath = getPathForURI(this.jobConfDirPath, uri);
        return this.converter.apply(loader.loadPullFile(targetJobSpecFullPath, this.sysConfig, shouldLoadGlobalConf()));
      } catch (FileNotFoundException e) {
        throw new JobSpecNotFoundException(uri);
      } catch (IOException e) {
        throw new RuntimeException("IO exception thrown on loading single job configuration file:" + e.getMessage());
      }
    }
docs: Fetch single job file based on its URI,
  return null requested URI not existed
  @param uri The relative Path to the target job configuration.
  @return