What Is Timer Together With Timertask Inwards Coffee – Tutorial Example
Timer inwards Java is a utility shape which is used to schedule tasks for both 1 fourth dimension as well as repeated execution. Timer is similar to warning facility many people role inwards mobile phone. Just similar y'all tin receive got 1 fourth dimension warning or repeated alarm, You tin role java.util.Timer to schedule 1 fourth dimension undertaking or repeated task. In fact nosotros tin implement a Reminder utility using Timer inwards Java as well as that's what nosotros are going to encounter inwards this illustration of Timer inwards Java. Two classes java.util.Timer as well as java.util.TimerTask is used to schedule jobs inwards Java as well as forms Timer API. TimerTask is actual undertaking which is executed yesteryear Timer. Similar to Thread inwards Java, TimerTask every bit good implements Runnable interface as well as overrides run method to specify undertaking details. This Java tutorial volition every bit good highlight difference betwixt Timer as well as TimerTask shape as well as explains how Timer industrial plant inwards Java. By the means departure betwixt Timer as well as Thread is every bit good a popular Java questions on fresher score interviews.
What is Timer as well as TimerTask inwards Java
Timer inwards Java is a utility shape variety java.util bundle which provides facility to schedule undertaking at whatever fourth dimension inwards future. As I said earlier, Timer is analogues to warning clock y'all setup inwards your smartphone. Just similar warning tin hold upwards either 1 fourth dimension or recurring, You tin every bit good schedule undertaking for 1 fourth dimension as well as recurring fourth dimension interval using Timer API. Timer provides method to schedule Task where undertaking is illustration of TimerTask class, which implements Runnable interface and overrides run() method to define undertaking which is called on scheduled time.How Timer industrial plant inwards Java
Timer shape inwards Java maintains a background Thread (this could hold upwards either daemon thread or user thread, based on how y'all created your Timer object), every bit good called every bit timer's undertaking execution thread. For each Timer at that spot would hold upwards corresponding undertaking processing Thread which run scheduled undertaking at specified time. If your Timer thread is non daemon thence it volition halt your application from exits until it completes all schedule task. Its recommended that TimerTask should non hold upwards really long otherwise it tin proceed this thread busy as well as non allow other scheduled undertaking to larn completed. This tin delay execution of other scheduled task, which may queue upwards as well as execute inwards quick succession 1 time offending undertaking completed.
Difference betwixt Timer as well as TimerTask inwards Java
I receive got seen programmers getting confused betwixt Timer as well as TimerTask, which is quite unnecessary because these 2 are altogether different. You only demand to remember:
1) Timer inwards Java schedules as well as execute TimerTask which is an implementation of Runnable interface as well as overrides run method to defined actual undertaking performed yesteryear that TimerTask.
2) Both Timer as well as TimerTask provides cancel() method. Timer's cancel() method cancels whole timer piece TimerTask's 1 cancels solely a exceptional task. I mean value this is the wroth noting departure betwixt Timer as well as TimerTask inwards Java.
Canceling Timer inwards Java
You tin cancel Java Timer yesteryear calling cancel() method of java.util.Timer class, this would lawsuit inwards following:
1) Timer volition non cancel whatever currently executing task.
2) Timer volition discard other scheduled undertaking as well as volition non execute them.
3) Once currently executing undertaking volition hold upwards finished, timer thread volition terminate gracefully.
4) Calling Timer.cancel() to a greater extent than than 1 fourth dimension volition non affect. 2nd telephone phone volition hold upwards ignored.
In add-on to cancelling Timer, You tin every bit good cancel private TimerTask yesteryear using cancel() method of TimerTask itself.
Timer as well as TimerTask illustration to schedule Tasks
Here is 1 illustration of Timer as well as TimerTask inwards Java to implement Reminder utility.
public class JavaReminder {
Timer timer;
public JavaReminder(int seconds) {
timer = new Timer(); //At this describe a novel Thread volition hold upwards created
timer.schedule(new RemindTask(), seconds*1000); //delay inwards milliseconds
}
class RemindTask extends TimerTask {
@Override
public void run() {
System.out.println("ReminderTask is completed yesteryear Java timer");
timer.cancel(); //Not necessary because nosotros telephone phone System.exit
//System.exit(0); //Stops the AWT thread (and everything else)
}
}
public static void main(String args[]) {
System.out.println("Java timer is near to start");
JavaReminder reminderBeep = new JavaReminder(5);
System.out.println("Remindertask is scheduled alongside Java timer.");
}
}
Output
Java timer is near to start
Remindertask is scheduled alongside Java timer.
ReminderTask is completed yesteryear Java timer //this volition impress later five seconds
Important points on Timer as well as TimerTask inwards Java
Now nosotros know what is Timer as well as TimerTask inwards Java, How to role them, How to cancel thence as well as got an agreement on How Timer industrial plant inwards Java. It’s skilful fourth dimension to revise Timer as well as TimerTask.
1.One Thread volition hold upwards created corresponding ot each Timer inwards Java, which could hold upwards either daemon or user thread.
2.You tin schedule multiple TimerTask alongside 1 Timer.
3.You tin schedule undertaking for either 1 fourth dimension execution or recurring execution.
4.TimerTask.cancel() cancels solely that exceptional task, piece Timer.cancel() cancel all undertaking scheduled inwards Timer.
5.Timer inwards Java volition throw IllegalStateException if y'all endeavour to schedule undertaking on a Timer which has been cancelled or whose Task execution Thread has been terminated.
That's all on what is Timer as well as TimerTask inwards Java as well as departure betwixt Timer as well as TimerTask inwards Java. Good agreement of Timer API is required yesteryear Java programmer to accept maximum wages of scheduling characteristic provided yesteryear Timer. They are essential as well as tin hold upwards used inwards multifariousness of ways e.g. to periodically take away build clean cache, to perform timely chore etc.
Further Learning
Multithreading as well as Parallel Computing inwards Java
Java Concurrency inwards Practice - The Book
How to role CountDownLatch inwards Java
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