Java Scheduler

http://www.quartz-scheduler.org/documentation/quartz-2.x/cookbook/SchedulerListeners.html
org.quartz.core.QuartzScheduler.pauseJob(JobKey)
public void pauseJob(JobKey jobKey) throws SchedulerException {
    validateState();

    resources.getJobStore().pauseJob(jobKey);
    notifySchedulerThread(0L);
    notifySchedulerListenersPausedJob(jobKey);
}

scheduler.getListenerManager().addSchedulerListener(mySchedListener);

public class MyOtherSchedulerListener extends SchedulerListenerSupport {

    @Override
    public void schedulerStarted() {
        // do something with the event
    }

    @Override
    public void schedulerShutdown() {
        // do something with the event
    }

    @Override
    public void jobScheduled(Trigger trigger) {
        // do something with the event
    }

}

https://www.mkyong.com/java/quartz-joblistener-example/

public class HelloJob implements Job
{
 public void execute(JobExecutionContext context)
 throws JobExecutionException {

  System.out.println("Hello Quartz! 123");

  //Throw exception for testing
  throw new JobExecutionException("Testing Exception");
 }

}