How to Conditionally Enable or Disable Scheduled Jobs in Spring

How to stop a scheduled task that was started using @Scheduled annotation?

Option 1: Using a post processor

Supply ScheduledAnnotationBeanPostProcessor and explicitly invoke postProcessBeforeDestruction(Object bean, String beanName), for the bean whose scheduling should be stopped.

Option 2: Maintaining a map of target beans to its Future

private final Map<Object, ScheduledFuture<?>> scheduledTasks =
        new IdentityHashMap<>();

@Scheduled(fixedRate = 2000)
public void fixedRateJob() {
    System.out.println("Something to be done every 2 secs");
}

@Bean
public TaskScheduler poolScheduler() {
    return new CustomTaskScheduler();
}

class CustomTaskScheduler extends ThreadPoolTaskScheduler {

    @Override
    public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, long period) {
        ScheduledFuture<?> future = super.scheduleAtFixedRate(task, period);

        ScheduledMethodRunnable runnable = (ScheduledMethodRunnable) task;
        scheduledTasks.put(runnable.getTarget(), future);

        return future;
    }

    @Override
    public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Date startTime, long period) {
        ScheduledFuture<?> future = super.scheduleAtFixedRate(task, startTime, period);

        ScheduledMethodRunnable runnable = (ScheduledMethodRunnable) task;
        scheduledTasks.put(runnable.getTarget(), future);

        return future;
    }
}

When the scheduling for a bean has to be stopped, you can lookup the map to get the corresponding Future to it and explicitly cancel it.

How to disable @Scheduled method via properties file?

Empty string is an incorrect cron expression. If you want to disable scheduler in particular condition just use @Profile annotation or if you have to operate on property use @ConditionalOnProperty annotation from Spring Boot.

@Component
@ConditionalOnProperty(prefix = "spring.cron", name = "expression")
public class MyScheduler {
   @Scheduled(cron = "${spring.cron.expression}")
   public void demonJob() throws .. { .. }
}

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