Scheduling a task in java for specified date periodically?

Question

I need schedule a task for specified date.For example task must be invoked after 2 days at 03:00:00.But i need it periodically.Each 2 days at 03:00:00.

ExecutorService provides delay time and periodic task execution but it doesn't provide me specify date and time.So i have to implement to calculate delay time.

Is there any ready to use library?

Answer 1

Most developers use Quartz for this kind of things.

Here is how you call Quartz to execute a task every 2 days at 03:00:00 :

trigger = newTrigger()
    .withIdentity("trigger3", "group1")
    .startAt(tomorrowAt(3, 0, 0)  // 03:00:00 tomorrow
    .withSchedule(calendarIntervalSchedule()
            .withIntervalInDays(2)) // interval is set in calendar days
    .build();

Documentation:
http://www.quartz-scheduler.org/documentation/quartz-2.2.x/cookbook/BiDailyTrigger

Quartz is open source and has many triggers and backends available.
It also has a big and vibrant community, and has been popular for at least 10 years already.