When we change the system time to past(say 1 hour before), the ScheduledThreadPoolExecutor starts consuming more CPU (around 95-100%).)

[Shikari0744]

Affects: <Spring Framework version>

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Below is the code :

final ThreadFactory threadFactory = new ThreadFactoryBuilder()
                .setNameFormat("XXX_THREAD")
                .setDaemon(true)
                .build();

        // Intentionally 1 thread
        ScheduledThreadPoolExecutor scheduledExecutor = new ScheduledThreadPoolExecutor(1, threadFactory);
        scheduledExecutor.setContinueExistingPeriodicTasksAfterShutdownPolicy(false);
        scheduledExecutor.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
        scheduledExecutor.setRemoveOnCancelPolicy(true);
        scheduledExecutor.setRejectedExecutionHandler(new DiscardPolicy());
        return scheduledExecutor;

scheduledExecutor.scheduleWithFixedDelay(this::runUpdateJob, 1, 1, TimeUnit.SECONDS);

The moment we change the system time to past (say 1 hour before current time), it starts affecting CPU resources(around 95%). The similar thing could happen during Daylight Saving also where time shifts to 1 hour past. Although, its gets normal when the past time elapsed.

Using JDK 1.8.0_202