How to call a method after some specific interval of time in Java

Question

Here is the use case:

I am using Java (with Spring)

Once the user (through a web-app) confirms to the subscription, I want to send him an email exactly after 30 mins.

Now how to do this? Do I need a message broker? or something like ScheduledExecutorService? Do I need some sort of queue?

Please advise.

I think a better title could be `"How to send mail, 30 minutes after an event."` — Nishant, Jul 28 '11 at 12:04
please send me your code if you have completed my id is manisathasivam@gmail.com — Mani, Jan 06 '15 at 06:16

score 4 · Accepted Answer · answered Jul 28 '11 at 12:03

4

Can look into quartz scheduler for this.

By the way a common strategy is to send a bulk of all pending mails in bulk in every 30 minutes or so. Quartz can help in do that as well.

answered Jul 28 '11 at 12:03

Nishant

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thanks, but how will this happen actually? Am I right in assuming that at occurance of every event, a new thread will be created which will wait for 30 mins, then sends the mail and then die? – adi Jul 28 '11 at 13:19
can we do this using ScheduledExecutorService? – adi Jul 28 '11 at 13:20
@adi I am not sure about exact inner workings of Quartz, but rest assured, it is super efficient... I have used it to drive couple of thousands jobs without any significant resource depletion. As far as the specific mailing jobs are concerned... I guess Quartz would do great. I never used ScheduledExecutorService, so can't honestly comment on it. – Nishant Jul 28 '11 at 14:12

score 2 · Answer 2 · answered Jan 27 '16 at 05:58

2

Create an object for Timer

 private Timer myTimer;

in main method

myTimer = new Timer();
    myTimer.schedule(new TimerTask() {
        @Override
        public void run() {
           //your method
        }

    }, 0, 200);

answered Jan 27 '16 at 05:58

Muhammed Fasil

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Good answer. Day saved. – 4xMafole Jul 16 '21 at 19:02

score 2 · Answer 3 · answered Jul 28 '11 at 12:04

2

You can use the Quartz Scheduler. Its fairly easy to use. You can schedule something every week or ever 30 minutes or whatever you want basically.

answered Jul 28 '11 at 12:04

RMT

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score 0 · Answer 4 · edited Aug 04 '11 at 13:09

0

It is not that the thread will die after sending the mail. When you configure Quartz, a new thread will automatically be created and will execute the assigned task on specified interval. Or else you use Timer class also. It is very easy to use.

    Timer timer = new Timer(); // Get timer

    long delay = 30 * 60 * 1000; // 3o min delay

    // Schedule the two timers to run with different delays.
    timer.schedule(new MyTask(), 0, delay);

...................



class MyTask extends TimerTask {

    public void run() {
        // business logic
        // send mail here
    }
}

edited Aug 04 '11 at 13:09

RMT

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answered Jul 28 '11 at 15:14

Partha

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what will happen to the thread if it is not dead after sending the mail? will I have hundreds on threads after a while? – adi Jul 29 '11 at 10:49
A separate thread will be running and when time ticks Task will gets executed. When you create a timer and it is scheduled, it runs in the background and executes the task every after specified interval. Try the following example public class Main { public static void main(String[] args) { Timer timer = new Timer(); long delay = 1000; // 1 sec delay timer.schedule(new MyTask(), 0, delay); while(true){ } } } public class MyTask extends TimerTask { public void run() { // business logic System.out.println("Mail sent"); } } – Partha Jul 29 '11 at 16:16
that works well but what about if I need to change times? For instance, I want delay time to be in the range of two time. – grep Oct 23 '15 at 16:13

How to call a method after some specific interval of time in Java

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