timer and timertask in java

Timer and TimerTask in Java

Timer and TimerTask in Java play crucial roles in managing time-based operations. Timer allows you to schedule tasks to be executed at specific intervals, while TimerTask represents the task to be performed. This article provides a comprehensive introduction to Timer and TimerTask in Java, exploring their functionalities and usage in various scenarios.

Timer in Java is a utility class that’s used to schedule duties for each
one time and repeated execution.
Timer is analogous
to the alarm facility many individuals use in cell phones. Identical to you may have one
time alarm or repeated alarm, You need to use
java.util.Timer to
schedule a time job or repeated job. In truth, we will implement a
Reminder utility
utilizing Timer in Java and that is what we’re going to see on this instance of
Timer in Java. Two courses java.util.Timer and java.util.TimerTask is used to
schedule jobs in Java and types Timer API. 
The TimerTask is an precise job that’s executed by Timer. Just like Thread in JavaTimerTask additionally implements the Runnable interface and overrides run methodology to specify a job particulars. 

This Java tutorial may also spotlight the distinction between Timer and TimerTask class and explains how Timer
works in Java. By the best way, the distinction between Timer and Thread can also be a in style
Java questions on fresher-level interviews.

What’s Timer and TimerTask in Java

Timer in Java is a utility class from java.util bundle
which offers the power to schedule duties at any time sooner or later. As I mentioned
Timer is analog to the alarm clock you arrange in your smartphone. 

Identical to alarm may be both one time or recurring, You can even schedule job
for one time and recurring time interval utilizing Timer API. Timer offers methodology
to schedule Job the place the duty is an occasion of
TimerTask class,
which implements the 
Runnable interface and overridesrun() methodology to
outline job which known as on scheduled time.

How Timer works in Java?

Timer class in Java maintains a background Thread (this might be either daemon thread or person thread,
primarily based on the way you created your Timer object), additionally known as timer’s job
execution thread. For every Timer, there can be a corresponding job processing Thread that runs the scheduled
job on the specified time. 

In case your Timer thread just isn’t daemon then it is going to cease
your utility from exits till it completes all scheduled duties. It is
beneficial that TimerTask shouldn’t be very lengthy in any other case it could possibly hold
this thread busy and never enable different scheduled duties to get accomplished. 

This could
delay the execution of different scheduled duties, which can queue up and execute in
fast succession as soon as the offending job is accomplished.

Here’s a good diagram which illustrate how Timer works in Java:


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Distinction between Timer and TimerTask in Java

I’ve seen programmers getting confused between Timer and TimerTask, which is
fairly pointless as a result of these two are altogether totally different. You simply have to
bear in mind:

1) Timer in Java schedules and execute TimerTask which is
an implementation of Runnable interface and overrides
run methodology to outline the precise job carried out by that

2) Each Timer and TimerTask present a cancel() methodology. Timer’s
cancel() methodology cancels the entire timer whereas TimerTask’s one cancels solely a
specific job. I feel that is the value noting distinction between
Timer and TimerTask in Java.

Additionally, here’s a good desk which highlights all of the distinction between Timer and TimerTask in Java:


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Timer in Java

You may cancel Java Timer by calling the cancel() methodology of java.util.Timer class,
this is able to consequence within the following:

1) Timer is not going to cancel any at present executing job.

2) Timer will discard different scheduled duties and can
not execute them.

3) As soon as the at present executing job might be completed, the timer thread will
terminate gracefully.

4) Calling Timer.cancel() multiple time is not going to
have an effect on. the second name might be ignored.

Along with canceling Timer, You can even cancel
particular person
TimerTask by utilizing the cancel() methodology of TimerTask itself. You may additional see these Java Multithreading programs to be taught extra about Thread and TimerTask in Java. 


and TimerTask instance to schedule Duties

Right here is one instance of Timer and TimerTask in Java to implement Reminder

public class JavaReminder {

Timer timer;

public JavaReminder(int seconds) {

timer = new Timer();//At this line a brand new Thread might be

timer.schedule(new RemindTask(), seconds*1000); //delay in


class RemindTask extends TimerTask {


public void run() {

is accomplished by Java timer”

timer.cancel(); //Not mandatory
as a result of we name System.exit

//Stops the AWT thread (and every little thing else)



public static void predominant(String args[]) {

timer is about to begin”

= new JavaReminder(5);

is scheduled with Java timer.”




Java timer is about to begin

Remindertask is scheduled with a Java timer.

ReminderTask is accomplished by Java timer//it will print after 5 seconds

factors on Timer and TimerTask in Java

Timer and TimerTask example in JavaNow we all know what’s Timer and TimerTask in Java,
The right way to use them, The right way to cancel then and received an understanding of How Timer works
in Java. It’s a great time to revise the 
Timer and TimerTask.

1. One Thread might be created corresponding ot every Timer in Java, which may
be both daemon or person thread.

2.You may schedule a number of TimerTask with one

3.You may schedule duties for both one-time execution or recurring

4.TimerTask.cancel() cancels solely that
specific job, whereas
Timer.cancel() cancel all job scheduled in

5. Timer in Java will throw IllegalStateException when you attempt
to schedule a job on a Timer that has been canceled or whose Job execution Thread
has been terminated.

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That is all on what’s Timer and TimerTask in Java
and the distinction between
Timer and TimerTask in Java. understanding of Timer API is required by Java programmers to take most
benefit of scheduling options supplied by Timer. They’re important and might
be utilized in quite a lot of methods e.g. to periodically take away clear cache,to carry out well timed jobs, and so on.

Different Java Multithreading Tutorials from Javarevisited Weblog

Also Read : Distinction between Thread vs Runnable interface in Java

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