code: public List<JobKey> getAllJobKeys() throws MangooSchedulerException {
          Objects.requireNonNull(this.quartzScheduler, Required.SCHEDULER.toString());
          
          List<JobKey> jobKeys = new ArrayList<>();
          try {
              for (String groupName : this.quartzScheduler.getJobGroupNames()) {
                  jobKeys.addAll(this.quartzScheduler.getJobKeys(GroupMatcher.jobGroupEquals(groupName)));
              }   
          } catch (SchedulerException e) {
              throw new MangooSchedulerException(e);
          }
          
          return jobKeys;
      }
docs: Retrieves a list of all JobKeys from the Quartz Scheduler
  
  @return List of all JobKey objects
  @throws MangooSchedulerException if an errors occurs during access to the scheduler