code: @Override
    public JobDetail retrieveJob(String jobKey) {
  
      synchronized (lock) {
        JobWrapper jw = jobsByKey.get(jobKey);
        return (jw != null) ? (JobDetail) jw.jobDetail.clone() : null;
      }
    }
docs: Retrieve the <code>{@link org.quartz.jobs.JobDetail}</code> for the given <code>
  {@link org.quartz.jobs.Job}</code>.
  
  @return The desired <code>Job</code>, or null if there is no match.