code: public void resolveBeanClass(ScheduleRule scheduleRule) throws IllegalRuleException {
          String beanId = scheduleRule.getSchedulerBeanId();
          if (beanId != null) {
              Class<?> beanClass = resolveBeanClass(beanId, scheduleRule);
              if (beanClass != null) {
                  scheduleRule.setSchedulerBeanClass(beanClass);
                  reserveBeanReference(beanClass, scheduleRule);
              } else {
                  reserveBeanReference(beanId, scheduleRule);
              }
          }
      }
docs: Resolve bean class for the schedule rule.
  
  @param scheduleRule the schedule rule
  @throws IllegalRuleException if an illegal rule is found