Question

I need to run a particular program once in a week,once in a month and once in a while

CronTrigger trigger = newTrigger()
        .withIdentity("trigger1", "group1")
        .withSchedule(cronSchedule("0/20 * * * * ?"))
        .build();

What all changes should be done in the above code?particularly in this part("0/20 * * * * ?"))
please help

Answer 1

You’ll need to switch between multiple schedules depending on the user’s choice:

// Once a month (the first day at midnight)
0 0 0 1 * ? 

// Once a week (Sunday at midnight)
0 0 0 * * 1

// On a specific date (November 10, 2012)
0 0 0 10 11 ? 2012

You can of course change the zeroes to other values if you want to change the time. See a full guide here.