How do I schedule a task to run at periodic intervals

Question

I was trying some codes to implement a scheduled task and came up with these codes    import java util     class Task extends TimerTask         int count   1          run is a abstract method that defines task performed at scheduled time      public void run             System out println count     Mahendra Singh            count             class TaskScheduling       public static void main String   args           Timer timer   new Timer                Schedule to run after every 3 second 3000 millisecond         timer schedule  new Task    3000               My output    1     Mahendra Singh   I expected the compiler to print a series of Mahendra Singh at periodic interval of 3 s but despite waiting for around 15 minutes  I get only one output   How do I solve this out

User · Answer

timer scheduleAtFixedRate  new Task    1000 3000

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Use timer scheduleAtFixedRate  public void scheduleAtFixedRate TimerTask task                                  long delay                                  long period    Schedules the specified task for repeated fixed-rate execution  beginning after the specified delay  Subsequent executions take place at approximately regular intervals  separated by the specified period      In fixed-rate execution  each execution is scheduled relative to the scheduled execution time of the initial execution  If an execution is delayed for any reason  such as garbage collection or other background activity   two or more executions will occur in rapid succession to  catch up   In the long run  the frequency of execution will be exactly the reciprocal of the specified period  assuming the system clock underlying Object wait long  is accurate     Fixed-rate execution is appropriate for recurring activities that are sensitive to absolute time  such as ringing a chime every hour on the hour  or running scheduled maintenance every day at a particular time  It is also appropriate for recurring activities where the total time to perform a fixed number of executions is important  such as a countdown timer that ticks once every second for ten seconds  Finally  fixed-rate execution is appropriate for scheduling multiple repeating timer tasks that must remain synchronized with respect to one another    Parameters    task - task to be scheduled  delay - delay in milliseconds before task is to be executed  period - time in milliseconds between successive task executions     Throws    IllegalArgumentException - if delay is negative  or delay   System currentTimeMillis   is negative   IllegalStateException - if task was already scheduled or cancelled  timer was cancelled  or timer thread terminated

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Advantage of ScheduledExecutorService over Timer  I wish to offer you an alternative to Timer using - ScheduledThreadPoolExecutor  an implementation of the ScheduledExecutorService interface  It has some advantages over the Timer class  according to  Java in Concurrency        A Timer creates only a single thread for executing timer tasks  If a   timer task takes too long to run  the timing accuracy of other   TimerTask can suffer  If a recurring TimerTask is scheduled to run   every 10 ms and another Timer-Task takes 40 ms to run  the recurring   task either  depending on whether it was scheduled at fixed rate or   fixed delay  gets called four times in rapid succession after the   long-running task completes  or  misses  four invocations completely    Scheduled thread pools address this limitation by letting you provide   multiple threads for executing deferred and periodic tasks    Another problem with Timer is that it behaves poorly if a TimerTask throws an unchecked exception  Also  called  thread leakage      The Timer thread doesn t catch the exception  so an unchecked   exception thrown from a TimerTask terminates the timer thread  Timer   also doesn t resurrect the thread in this situation  instead  it   erroneously assumes the entire Timer was cancelled  In this case    TimerTasks that are already scheduled but not yet executed are never   run  and new tasks cannot be scheduled     And another recommendation if you need to build your own scheduling service  you may still be able to take advantage of the library by using a DelayQueue  a BlockingQueue implementation that provides the scheduling functionality of ScheduledThreadPoolExecutor  A DelayQueue manages a collection of Delayed objects  A Delayed has a delay time associated with it  DelayQueue lets you take an element only if its delay has expired  Objects are returned from a DelayQueue ordered by the time associated with their delay

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public void schedule TimerTask task long delay    Schedules the specified task for execution after the specified delay   you want   public void schedule TimerTask task  long delay  long period    Schedules the specified task for repeated fixed-delay execution  beginning after the specified delay  Subsequent executions take place at approximately regular intervals separated by the specified period

[java] How do I schedule a task to run at periodic intervals?

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