How to schedule a Task in Java

By Atul Rai | Last Updated: November 19, 2022 Previous       Next

In Java to run/execute a task periodically or at some interval, we can use the TimerTask class from its java.util package. TimerTask is an abstract class that implements Runnable interface.

For example, you have to print the current date and time every second or make an API call every second.

Related Post: Spring Task Scheduler Example using @Scheduled Annotation

Follow the below steps to schedule a task.

Step 1: Create a class and extend TimerTask.

class MyTask extends TimerTask

Step 2: Override its run() method and define your task inside the run() method which needs to be executed.

@Override
public void run() {
    LocalDateTime now = LocalDateTime.now();
    System.out.println("Current date & time is: " + now);
}

Step 3: Now create another class to run the task and instantiate Timer object.

Timer timer = new Timer();

Step 4: Assign scheduled task through Timer.shedule() method.

timer.schedule(new MyTask(), 0, 1000);

See the complete example.

package org.websparrow.timer;

import java.time.LocalDateTime;
import java.util.Timer;
import java.util.TimerTask;

public class TaskScheduler {

    public static void main(String[] args) {

        // Initialize the Timer object
        Timer timer = new Timer();
        // Schedule the task which execute on every 1 second interval
        timer.schedule(new MyTask(), 0, 1000);

    }
}

class MyTask extends TimerTask {

    // Define your task
    @Override
    public void run() {
        LocalDateTime now = LocalDateTime.now();
        System.out.println("Current date & time is: " + now);
    }
}

Output:

Current date & time is: 2022-11-19T14:01:57.856926100
Current date & time is: 2022-11-19T14:01:58.851819600
Current date & time is: 2022-11-19T14:01:59.863210100
Current date & time is: 2022-11-19T14:02:00.873723300
Current date & time is: 2022-11-19T14:02:01.885005100
Current date & time is: 2022-11-19T14:02:02.895217600
Current date & time is: 2022-11-19T14:02:03.906639800
Current date & time is: 2022-11-19T14:02:04.915792600
Current date & time is: 2022-11-19T14:02:05.928842400

References

1. Java – TaksTimer
2. Java – Timer