code: @Override
    public int compareTo(JobDetails otherJob) {
      if (otherJob == null) {
        return -1;
      }
      return new CompareToBuilder().append(this.jobKey, otherJob.getJobKey())
          .toComparison();
    }
docs: Compares two JobDetails objects on the basis of their JobKey
  
  @param other
  @return 0 if this JobKey is equal to the other JobKey,
  1 if this JobKey greater than other JobKey,
  -1 if this JobKey is less than other JobKey