code: @POST
    @Path(ServiceConstants.CANCEL)
    public Response cancel(@QueryParam("jobId") final long jobId) {
      return RestUtils.call(new RestUtils.RestCallable<Void>() {
        @Override
        public Void call() throws Exception {
          mJobMaster.cancel(jobId);
          return null;
        }
      }, ServerConfiguration.global());
    }
docs: Cancels a job.
  
  @param jobId the id of the job to cancel
  @return the response