How to run certain task every day at a particular time using ScheduledExecutorService

Question

I am trying to run a certain task everyday at 5 AM in the morning  So I decided to use ScheduledExecutorService for this but so far I have seen examples which shows how to run task every few minutes    And I am not able to find any example which shows how to run a task every day at a particular time  5 AM  in the morning and also considering the fact of daylight saving time as well -   Below is my code which will run every 15 minutes -   public class ScheduledTaskExample       private final ScheduledExecutorService scheduler   Executors          newScheduledThreadPool 1        public void startScheduleTask                   not using the taskHandle returned here  but it can be used to cancel       the task  or check if it s done  for recurring tasks  that s not       going to be very useful             final ScheduledFuture lt   gt  taskHandle   scheduler scheduleAtFixedRate          new Runnable                 public void run                     try                       getDataFromDatabase                     catch Exception ex                        ex printStackTrace      or loggger would be better                                            0  15  TimeUnit MINUTES              private void getDataFromDatabase             System out println  getting data                  public static void main String   args            ScheduledTaskExample ste   new ScheduledTaskExample            ste startScheduleTask              Is there any way  I can schedule a task to run every day 5 AM in the morning using ScheduledExecutorService considering the fact of daylight saving time as well   And also TimerTask is better for this or ScheduledExecutorService

User · Answer

If you don t have the luxury of being able to use Java 8  the following will do what you need   public class DailyRunnerDaemon      private final Runnable dailyTask     private final int hour     private final int minute     private final int second     private final String runThreadName      public DailyRunnerDaemon Calendar timeOfDay  Runnable dailyTask  String runThreadName             this dailyTask   dailyTask        this hour   timeOfDay get Calendar HOUR OF DAY         this minute   timeOfDay get Calendar MINUTE         this second   timeOfDay get Calendar SECOND         this runThreadName   runThreadName           public void start              startTimer             private void startTimer               new Timer runThreadName  true  schedule new TimerTask                     Override          public void run                          dailyTask run                startTimer                        getNextRunTime               private Date getNextRunTime              Calendar startTime   Calendar getInstance          Calendar now   Calendar getInstance          startTime set Calendar HOUR OF DAY  hour         startTime set Calendar MINUTE  minute         startTime set Calendar SECOND  second         startTime set Calendar MILLISECOND  0          if startTime before now     startTime equals now                    startTime add Calendar DATE  1                  return startTime getTime             It doesn t require any external libs  and will account for daylight savings  Simply pass in the time of day you want to run the task as a Calendar object  and the task as a Runnable  For example   Calendar timeOfDay   Calendar getInstance    timeOfDay set Calendar HOUR OF DAY  5   timeOfDay set Calendar MINUTE  0   timeOfDay set Calendar SECOND  0    new DailyRunnerDaemon timeOfDay  new Runnable         Override    public void run              try                    call whatever your daily task is here         doHousekeeping                  catch Exception e                  logger error  An error occurred performing daily housekeeping   e                    daily-housekeeping      N B  the timer task runs in a Daemon thread which is not recommended for doing any IO  If you need to use a User thread  you will need to add another method which cancels the timer   If you have to use a ScheduledExecutorService  simply change the startTimer method to the following   private void startTimer        Executors newSingleThreadExecutor   schedule new Runnable              Thread currentThread   setName runThreadName         dailyTask run          startTimer          getNextRunTime   getTime   - System currentTimeMillis       TimeUnit MILLISECONDS       I am not sure of the behaviour but you may need a stop method which calls shutdownNow if you go down the ScheduledExecutorService route  otherwise your application may hang when you try to stop it

User · Answer

Have you considered using something like Quartz Scheduler   This library has a mechanism for scheduling tasks to run at a set period of time every day using a cron like expression  take a look at CronScheduleBuilder    Some example code  not tested    public class GetDatabaseJob implements InterruptableJob       public void execute JobExecutionContext arg0  throws JobExecutionException               getFromDatabase             public class Example       public static void main String   args                JobDetails job   JobBuilder newJob GetDatabaseJob class               Schedule to run at 5 AM every day         ScheduleBuilder scheduleBuilder                    CronScheduleBuilder cronSchedule  0 0 5                  Trigger trigger   TriggerBuilder newTrigger                    withSchedule scheduleBuilder  build             Scheduler scheduler   StdSchedulerFactory getDefaultScheduler            scheduler scheduleJob job  trigger            scheduler start              There s a bit more work upfront  and you may need to rewrite your job execution code  but it should give you more control over how you want you job to run   Also it would be easier to change the schedule should you need to

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Java8  My upgrage version from top answer     Fixed situation when Web Application Server doens t want to stop  because of threadpool with idle thread Without recursion Run task with your custom local time  in my case  it s Belarus  Minsk            Execute   link AppWork  once per day      lt p gt     Created by aalexeenka on 29 12 2016      public class OncePerDayAppWorkExecutor        private static final Logger LOG   AppLoggerFactory getScheduleLog OncePerDayAppWorkExecutor class        private ScheduledExecutorService executorService   Executors newScheduledThreadPool 1        private final String name      private final AppWork appWork       private final int targetHour      private final int targetMin      private final int targetSec       private volatile boolean isBusy   false      private volatile ScheduledFuture lt   gt  scheduledTask   null       private AtomicInteger completedTasks   new AtomicInteger 0        public OncePerDayAppWorkExecutor              String name              AppWork appWork              int targetHour              int targetMin              int targetSec                 this name    Executor      name                this appWork   appWork           this targetHour   targetHour          this targetMin   targetMin          this targetSec   targetSec             public void start             scheduleNextTask doTaskWork                private Runnable doTaskWork             return    - gt                LOG info name          completedTasks get        start      minskDateTime                 try                   isBusy   true                  appWork doWork                    LOG info name     finish work in     minskDateTime                   catch  Exception ex                    LOG error name     throw exception in     minskDateTime    ex                 finally                   isBusy   false                            scheduleNextTask doTaskWork                 LOG info name          completedTasks get        finish      minskDateTime                 LOG info name     completed tasks      completedTasks incrementAndGet                           private void scheduleNextTask Runnable task            LOG info name     make schedule in     minskDateTime             long delay   computeNextDelay targetHour  targetMin  targetSec           LOG info name     has delay in     delay           scheduledTask   executorService schedule task  delay  TimeUnit SECONDS              private static long computeNextDelay int targetHour  int targetMin  int targetSec            ZonedDateTime zonedNow   minskDateTime            ZonedDateTime zonedNextTarget   zonedNow withHour targetHour  withMinute targetMin  withSecond targetSec  withNano 0            if  zonedNow compareTo zonedNextTarget   gt  0                zonedNextTarget   zonedNextTarget plusDays 1                      Duration duration   Duration between zonedNow  zonedNextTarget           return duration getSeconds               public static ZonedDateTime minskDateTime             return ZonedDateTime now ZoneId of  Europe Minsk                public void stop             LOG info name     is stopping             if  scheduledTask    null                scheduledTask cancel false                     executorService shutdown            LOG info name     stopped             try               LOG info name     awaitTermination  start  isBusy       isBusy                        wait one minute to termination if busy             if  isBusy                    executorService awaitTermination 1  TimeUnit MINUTES                           catch  InterruptedException ex                LOG error name     awaitTermination exception   ex             finally               LOG info name     awaitTermination  finish

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Just to add up on Victor s answer   I would recommend to add a check to see  if the variable  in his case the long midnight  is higher than 1440  If it is  I would omit the  plusDays 1   otherwise the task will only run the day after tomorrow   I did it simply like this   Long time   final Long tempTime   LocalDateTime now   until LocalDate now   plusDays 1  atTime 7  0   ChronoUnit MINUTES   if  tempTime  gt  1440        time   LocalDateTime now   until LocalDate now   atTime 7  0   ChronoUnit MINUTES     else       time   tempTime

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In Java 8   scheduler   Executors newScheduledThreadPool 1      Change here for the hour you want ---------------------------------- at          Long midnight LocalDateTime now   until LocalDate now   plusDays 1  atStartOfDay    ChronoUnit MINUTES   scheduler scheduleAtFixedRate this  midnight  1440  TimeUnit MINUTES

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You can use a simple date parse  if the time of the day is before now  let s start tomorrow      String timeToStart    12 17 30     SimpleDateFormat format   new SimpleDateFormat  yyyy-MM-dd  at  HH mm ss      SimpleDateFormat formatOnlyDay   new SimpleDateFormat  yyyy-MM-dd      Date now   new Date      Date dateToStart   format parse formatOnlyDay format now      at     timeToStart     long diff   dateToStart getTime   - now getTime      if  diff  lt  0           tomorrow     Date tomorrow   new Date        Calendar c   Calendar getInstance        c setTime tomorrow       c add Calendar DATE  1       tomorrow   c getTime        dateToStart   format parse formatOnlyDay format tomorrow      at     timeToStart       diff   dateToStart getTime   - now getTime           ScheduledExecutorService scheduler   Executors newScheduledThreadPool 1                 scheduler scheduleAtFixedRate new MyRunnableTask    TimeUnit MILLISECONDS toSeconds diff                                      24 60 60  TimeUnit SECONDS

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As with the present java SE 8 release with it s excellent date time API with java time these kind of calculation can be done more easily instead of using    java util Calendar and java util Date     Use date time class s i e  LocalDateTime of this new API Use ZonedDateTime class to handle Time Zone specific calculation including Daylight Saving issues  You will find tutorial and example here      Now as a sample example for scheduling a task with your use case   ZonedDateTime now   ZonedDateTime now ZoneId of  America Los Angeles     ZonedDateTime nextRun   now withHour 5  withMinute 0  withSecond 0   if now compareTo nextRun   gt  0      nextRun   nextRun plusDays 1    Duration duration   Duration between now  nextRun   long initalDelay   duration getSeconds     ScheduledExecutorService scheduler   Executors newScheduledThreadPool 1               scheduler scheduleAtFixedRate new MyRunnableTask        initalDelay      TimeUnit DAYS toSeconds 1       TimeUnit SECONDS     The initalDelay is computed to ask the scheduler to delay the execution in TimeUnit SECONDS  Time difference issues with unit milliseconds and below seems to be negligible for this use case  But you can still make use of duration toMillis   and TimeUnit MILLISECONDS for handling the scheduling computaions in milliseconds       And also TimerTask is better for this or ScheduledExecutorService    NO  ScheduledExecutorService seemingly better than TimerTask  StackOverflow has already an answer for you    From  PaddyD      You still have the issue whereby you need to restart this twice a year   if you want it to run at the right local time  scheduleAtFixedRate   won t cut it unless you are happy with the same UTC time all year    As it is true and  PaddyD already has given a workaround  1 to him   I am providing a working example with Java8 date time API with ScheduledExecutorService  Using daemon thread is dangerous   class MyTaskExecutor       ScheduledExecutorService executorService   Executors newScheduledThreadPool 1       MyTask myTask      volatile boolean isStopIssued       public MyTaskExecutor MyTask myTask                  myTask   myTask               public void startExecutionAt int targetHour  int targetMin  int targetSec                Runnable taskWrapper   new Runnable                  Override             public void run                                  myTask execute                    startExecutionAt targetHour  targetMin  targetSec                                     long delay   computeNextDelay targetHour  targetMin  targetSec           executorService schedule taskWrapper  delay  TimeUnit SECONDS              private long computeNextDelay int targetHour  int targetMin  int targetSec                 LocalDateTime localNow   LocalDateTime now            ZoneId currentZone   ZoneId systemDefault            ZonedDateTime zonedNow   ZonedDateTime of localNow  currentZone           ZonedDateTime zonedNextTarget   zonedNow withHour targetHour  withMinute targetMin  withSecond targetSec           if zonedNow compareTo zonedNextTarget   gt  0              zonedNextTarget   zonedNextTarget plusDays 1            Duration duration   Duration between zonedNow  zonedNextTarget           return duration getSeconds               public void stop                 executorService shutdown            try               executorService awaitTermination 1  TimeUnit DAYS             catch  InterruptedException ex                Logger getLogger MyTaskExecutor class getName    log Level SEVERE  null  ex                       Note    MyTask is an interface with function execute   While stopping ScheduledExecutorService  Always use awaitTermination after invoking shutdown on it  There s always a likelihood your task is stuck   deadlocking and the user would wait forever    The previous example I gave with Calender was just an idea which I did mention  I avoided exact time calculation and Daylight saving issues  Updated the solution on per the complain of  PaddyD

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The following example work for me  public class DemoScheduler        public static void main String   args                Create a calendar instance         Calendar calendar   Calendar getInstance                Set time of execution  Here  we have to run every day 4 20 PM  so             setting all parameters          calendar set Calendar HOUR  8           calendar set Calendar MINUTE  0           calendar set Calendar SECOND  0           calendar set Calendar AM PM  Calendar AM            Long currentTime   new Date   getTime                Check if current time is greater than our calendar s time  If So             then change date to one day plus  As the time already pass for            execution          if  calendar getTime   getTime    lt  currentTime                calendar add Calendar DATE  1                         Calendar is scheduled for future  so  it s time is higher than            current time          long startScheduler   calendar getTime   getTime   - currentTime              Setting stop scheduler at 4 21 PM  Over here  we are using current            calendar s object  so  date and AM PM is not needed to set         calendar set Calendar HOUR  5           calendar set Calendar MINUTE  0           calendar set Calendar AM PM  Calendar PM               Calculation stop scheduler         long stopScheduler   calendar getTime   getTime   - currentTime              Executor is Runnable  The code which you want to run periodically          Runnable task   new Runnable                   Override             public void run                      System out println  test                                         Get an instance of scheduler         final ScheduledExecutorService scheduler   Executors newScheduledThreadPool 1              execute scheduler at fixed time          scheduler scheduleAtFixedRate task  startScheduler  stopScheduler  MILLISECONDS             reference  https   chynten wordpress com 2016 06 03 java-scheduler-to-run-every-day-on-specific-time

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Why to complicate a situation if you can just write like it   yes - gt  low cohesion  hardcoded - gt  but it is a example and unfortunately with imperative way   For additional info read code example at below     package timer test   import org slf4j Logger  import org slf4j LoggerFactory   import java time Duration  import java time LocalDate  import java time LocalDateTime  import java util concurrent     public class TestKitTimerWithExecuterService        private static final Logger log   LoggerFactory getLogger TestKitTimerWithExecuterService class        private static final ScheduledExecutorService executorService    Executors newSingleThreadScheduledExecutor      equal to   gt  newScheduledThreadPool 1   Executor service with one Thread      private static ScheduledFuture lt   gt  future     why  because scheduleAtFixedRate will return you it and you can act how you like           public static void main String args              log info  quot main thread start quot             Runnable task      - gt  log info  quot          Task running          quot             LocalDateTime now   LocalDateTime now             LocalDateTime whenToStart   LocalDate now   atTime 20  11      hour  minute          Duration duration   Duration between now  whenToStart            log info  quot WhenToStart       Now       Duration difference in second      quot  whenToStart  now  duration getSeconds              future   executorService scheduleAtFixedRate task                   duration getSeconds          difference in second - when to start a job                  2                            period                   TimeUnit SECONDS            try               TimeUnit MINUTES sleep 2       DanDig imitation of reality             cancelExecutor          after canceling Executor it will never run your job again           catch  InterruptedException e                e printStackTrace                      log info  quot main thread end quot                  public static void cancelExecutor             future cancel true           executorService shutdown             log info  quot Executor service goes to shut down quot

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You can use below class to schedule your task every day particular time   package interfaces   import java time LocalDate  import java time LocalDateTime  import java time temporal ChronoUnit  import java util Date  import java util concurrent Executors  import java util concurrent ScheduledExecutorService  import java util concurrent TimeUnit   public class CronDemo implements Runnable       public static void main String   args             Long delayTime           ScheduledExecutorService scheduler   Executors newScheduledThreadPool 1            final Long initialDelay   LocalDateTime now   until LocalDate now   plusDays 1  atTime 12  30   ChronoUnit MINUTES            if  initialDelay  gt  TimeUnit DAYS toMinutes 1                 delayTime   LocalDateTime now   until LocalDate now   atTime 12  30   ChronoUnit MINUTES             else               delayTime   initialDelay                     scheduler scheduleAtFixedRate new CronDemo    delayTime  TimeUnit DAYS toMinutes 1   TimeUnit MINUTES                Override     public void run             System out println  I am your job executin at     new Date

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I had a similar problem  I had to schedule bunch of tasks that should be executed during a day using ScheduledExecutorService   This was solved by one task starting at 3 30 AM scheduling all other tasks relatively to his current time  And rescheduling himself for the next day at 3 30 AM   With this scenario daylight savings are not an issue anymore

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What if your server goes down at 4 59AM and comes back at 5 01AM  I think it will just skip the run  I would recommend persistent scheduler like Quartz  that would store its schedule data somewhere  Then it will see that this run hasn t been performed yet and will do it at 5 01AM

[java] How to run certain task every day at a particular time using ScheduledExecutorService?

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