What Is Timer In Addition To 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 purpose inwards mobile phone. Just similar yous tin receive got 1 fourth dimension warning or repeated alarm, You tin purpose java.util.Timer to schedule 1 fourth dimension labor 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 run into inwards this representative 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 labor which is executed yesteryear Timer. Similar to Thread inwards Java, TimerTask equally good implements Runnable interface as well as overrides run method to specify labor details. This Java tutorial volition equally good highlight difference betwixt Timer as well as TimerTask shape as well as explains how Timer plant inwards Java. By the means deviation betwixt Timer as well as Thread is equally good a popular Java questions on fresher degree interviews.
What is Timer as well as TimerTask inwards Java
Timer inwards Java is a utility shape kind java.util bundle which provides facility to schedule labor at whatever fourth dimension inwards future. As I said earlier, Timer is analogues to warning clock yous setup inwards your smartphone. Just similar warning tin survive either 1 fourth dimension or recurring, You tin equally good schedule labor for 1 fourth dimension as well as recurring fourth dimension interval using Timer API. Timer provides method to schedule Task where labor is representative of TimerTask class, which implements Runnable interface and overrides run() method to define labor which is called on scheduled time.How Timer plant inwards Java
Timer shape inwards Java maintains a background Thread (this could survive either daemon thread or user thread, based on how yous created your Timer object), equally good called equally timer's labor execution thread. For each Timer in that place would survive corresponding labor processing Thread which run scheduled labor at specified time. If your Timer thread is non daemon thus it volition halt your application from exits until it completes all schedule task. Its recommended that TimerTask should non survive rattling long otherwise it tin proceed this thread busy as well as non allow other scheduled labor 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 labor 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 ii are altogether different. You simply 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 labor 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 entirely a exceptional task. I mean value this is the wroth noting deviation 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 effect inwards following:
1) Timer volition non cancel whatever currently executing task.
2) Timer volition discard other scheduled labor as well as volition non execute them.
3) Once currently executing labor volition survive finished, timer thread volition terminate gracefully.
4) Calling Timer.cancel() to a greater extent than than 1 fourth dimension volition non affect. minute telephone telephone volition survive ignored.
In add-on to cancelling Timer, You tin equally good cancel private TimerTask yesteryear using cancel() method of TimerTask itself.
Timer as well as TimerTask representative to schedule Tasks
Here is 1 representative 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 delineate a novel Thread volition survive 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 telephone System.exit
//System.exit(0); //Stops the AWT thread (and everything else)
}
}
public static void main(String args[]) {
System.out.println("Java timer is close to start");
JavaReminder reminderBeep = new JavaReminder(5);
System.out.println("Remindertask is scheduled alongside Java timer.");
}
}
Output
Java timer is close to start
Remindertask is scheduled alongside Java timer.
ReminderTask is completed yesteryear Java timer //this volition impress subsequently v 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 purpose them, How to cancel thus as well as got an agreement on How Timer plant inwards Java. It’s expert fourth dimension to revise Timer as well as TimerTask.
1.One Thread volition survive created corresponding ot each Timer inwards Java, which could survive either daemon or user thread.
2.You tin schedule multiple TimerTask alongside 1 Timer.
3.You tin schedule labor for either 1 fourth dimension execution or recurring execution.
4.TimerTask.cancel() cancels entirely that exceptional task, piece Timer.cancel() cancel all labor scheduled inwards Timer.
5.Timer inwards Java volition throw IllegalStateException if yous endeavour to schedule labor 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 deviation betwixt Timer as well as TimerTask inwards Java. Good agreement of Timer API is required yesteryear Java programmer to accept maximum payoff of scheduling characteristic provided yesteryear Timer. They are essential as well as tin survive used inwards diversity of ways e.g. to periodically take away construct clean cache, to perform timely labor etc.
Further Learning
Multithreading as well as Parallel Computing inwards Java
Java Concurrency inwards Practice - The Book
How to purpose CountDownLatch inwards Java
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