code: public JobRequest setPriority(Integer priority)
      {
          if (priority == null)
          {
              priority = 0;
              return this;
          }
          if (priority > Thread.MAX_PRIORITY || priority < Thread.MIN_PRIORITY)
          {
              throw new JqmInvalidRequestException("Priority must be between Thread.MIN_PRIORITY and Thread.MAX_PRIORITY");
          }
  
          this.priority = priority;
          return this;
      }
docs: <strong>Optional</strong><br>
  By default, JQM queues are pure FIFO. Setting a priority changes that: job instances with a higher priority always run before job
  instances with a lower priority (or no priority at all). Also, this is directly translated into Thread priority when the job instance
  actually runs.<br>
  Higher priority is better (runs before the others, has more CPU share).<br>
  Priority must be between {@link Thread#MIN_PRIORITY} and {@link Thread#MAX_PRIORITY}. To remove priority, set it to null.
  
  @param priority
  @return