197 Java TimerTask Class

Introduction

The Java TimerTask class represents a task that can be scheduled for one-time or repeated execution by a Timer.

Class declaration

Following is the declaration for java.util.TimerTask class −

public abstract class TimerTask
   extends Object
   implements Runnable

Class constructors

Sr.No.	Constructor & Description
1	protected TimerTask() This constructor creates a new timer task.

Class methods

Sr.No.	Method & Description
1	boolean cancel() This method cancels this timer task.
2	abstract void run() This method represents the action to be performed by this timer task.
3	long scheduledExecutionTime() This method returns the scheduled execution time of the most recent actual execution of this task.

Methods inherited

This class inherits methods from the following classes −

• java.util.Object

Running a Timer Task for a given Schedule Example

The following example shows the usage of Java Timer run() method to run the timer operation as per schedule. We've created a timer object using a CustomTimerTask object. CustomTimerTask is custom class extending TimerTask class and implements the run() method which will execute at scheduled time. Then we created a timer object and scheduled a task using scheduleAtFixedRate() to execute at every 100 milliseconds starting from now.

package com.codeheap;

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

public class TimerTaskDemo {
   public static void main(String[] args) {

      // creating timer task, timer
      TimerTask tasknew = new CustomTimerTask();
      Timer timer = new Timer();

      // scheduling the task
      timer.scheduleAtFixedRate(tasknew, new Date(), 100);

      try {
         Thread.sleep(500);
      } catch (InterruptedException e){
         // TODO Auto-generated catch block
         e.printStackTrace();
      }
   }
}

class CustomTimerTask extends TimerTask {

   @Override
   public void run() {
      System.out.println("working on");
   }  
}

Output

Let us compile and run the above program, this will produce the following result.

working on
working on
working on
working on
working on
working on