How to call a method on specific time in java?

Question

Is it possible to call a method in java at specific time? For example of I have a piece of code like this:

class Test{

    public static void main(String ar         


        

Answer 1

You could use the class Timer

From documentation:

A facility for threads to schedule tasks for future execution in a background thread. Tasks may be scheduled for one-time execution, or for repeated execution at regular intervals.

The method schedule(TimerTask task, Date time) is exactly what you want: Schedules the specified task for execution at the specified time.

If you need schedule in cron format, quartz would be a good solution. (quartz cron like schedule)

Answer 2

You can use a ScheduledExecutorService, which is "a more versatile replacement for the Timer/TimerTask combination" (according to Timer's javadoc):

long delay = ChronoUnit.MILLIS.between(LocalTime.now(), LocalTime.of(13, 5, 45));
ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
scheduler.schedule(task, delay, TimeUnit.MILLISECONDS);

Answer 3

Simple demo of java.util.Timer

Timer t=new Timer();
t.schedule(new TimerTask() {
    public void run() {
        foo();
    }
}, new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2012-07-06 13:40:20"));

Answer 4

It is possible. You can schedule a method at some time using Timer and TimerTask.

For example:

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 10);
calendar.set(Calendar.MINUTE, 30);
calendar.set(Calendar.SECOND, 0);

Date alarmTime = calendar.getTime();

Timer _timer = new Timer();
_timer.schedule(foo, alarmTime);

Refer these links:

• Timer
• TimerTask

Answer 5

Timer timer = new Timer();
Calendar calendar = Calendar.getInstance(); // gets a calendar using the default time zone and locale.
calendar.add(Calendar.SECOND, 5);
Date date = calendar.getTime();
timer.schedule(new TimerTask() {
    @Override
    public void run() {
        test();
    }
}, date);

Answer 6

If you are talking about SE then the Timer class might be what you are looking for http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Timer.html, available since Java 5.

If you need to time something in an application server context I would recommend having a look at EJB timers http://www.javabeat.net/2007/03/ejb-3-0-timer-services-an-overview/ available since EJB 3.0.

Alternatively, depending on what you are really trying to do, you could elaborate if using a cron job (or any other OS based timer method) would be more suitable, i.e. you don't want or can't have the VM running all the time.