code: private boolean tryLockJob(Properties properties) {
      try {
        if (Boolean.valueOf(properties.getProperty(ConfigurationKeys.JOB_LOCK_ENABLED_KEY, Boolean.TRUE.toString()))) {
          this.jobLockOptional = Optional.of(getJobLock(properties, new JobLockEventListener() {
            @Override
            public void onLost() {
              executeCancellation();
            }
          }));
        }
        return !this.jobLockOptional.isPresent() || this.jobLockOptional.get().tryLock();
      } catch (JobLockException ioe) {
        LOG.error(String.format("Failed to acquire job lock for job %s: %s", this.jobContext.getJobId(), ioe), ioe);
        return false;
      }
    }
docs: Try acquiring the job lock and return whether the lock is successfully locked.
  
  @param properties the job properties