Follow these steps to implement the example:

1. Create a class named Task that implements the Runnable interface:

        public class Task implements Runnable {

2. Declare a private int attribute named time:

        private final int time;

3. Declare a private Phaser attribute named phaser:

        private final Phaser phaser;

4. Implement the constructor of the class to initialize its attributes:

        public Task(int time, Phaser phaser) { 
          this.time=time; 
          this.phaser=phaser; 
        }

5. Implement the run() method. First, instruct the phaser attribute that the task starts its execution with the arrive() method:

        @Override 
        public void run() { 
 
          phaser.arrive();

6. Write a message in the console indicating the start of phase one. Put the thread to sleep for the number of seconds specified by the time attribute. Write a message in the console indicating the end of phase one. And, synchronize with the rest of the tasks using the arriveAndAwaitAdvance() method of the phaser attribute:

        System.out.printf("%s: Entering phase 1.
",
                          Thread.currentThread().getName()); 
        try { 
          TimeUnit.SECONDS.sleep(time); 
        } catch (InterruptedException e) { 
          e.printStackTrace(); 
        } 
        System.out.printf("%s: Finishing phase 1.
",
                          Thread.currentThread().getName()); 
        phaser.arriveAndAwaitAdvance();

7. Repeat this behavior in both second and third phases. At the end of the third phase, use the arriveAndDeregister() method instead of arriveAndAwaitAdvance():

        System.out.printf("%s: Entering phase 2.
",
                          Thread.currentThread().getName()); 
        try { 
          TimeUnit.SECONDS.sleep(time); 
        } catch (InterruptedException e) { 
          e.printStackTrace(); 
        } 
        System.out.printf("%s: Finishing phase 2.
",
                          Thread.currentThread().getName()); 
        phaser.arriveAndAwaitAdvance(); 
 
        System.out.printf("%s: Entering phase 3.
",
                          Thread.currentThread().getName()); 
        try { 
          TimeUnit.SECONDS.sleep(time); 
        } catch (InterruptedException e) { 
          e.printStackTrace(); 
        } 
        System.out.printf("%s: Finishing phase 3.
",
                          Thread.currentThread().getName()); 
 
        phaser.arriveAndDeregister();

8. Implement the main class of the example by creating a class named Main with a main() method:

        public class Main { 
 
          public static void main(String[] args) throws Exception {

9. Create a new Phaser object named phaser with three participants:

        Phaser phaser=new Phaser(3);

10. Create and launch three threads to execute three task objects:

        for (int i=0; i<3; i++) { 
          Task task=new Task(i+1, phaser); 
          Thread thread=new Thread(task); 
          thread.start(); 
        }

11. Create a loop with 10 steps to write information about the phaser object:

        for (int i=0; i<10; i++) {

12. Write information about the registered parties, the phase of the phaser, the arrived parties, and the unarrived parties:

        System.out.printf("********************
"); 
        System.out.printf("Main: Phaser Log
"); 
        System.out.printf("Main: Phaser: Phase: %d
",
                          phaser.getPhase()); 
        System.out.printf("Main: Phaser: Registered Parties: %d
",
                          phaser.getRegisteredParties()); 
        System.out.printf("Main: Phaser: Arrived Parties: %d
",
                          phaser.getArrivedParties()); 
        System.out.printf("Main: Phaser: Unarrived Parties: %d
",
                          phaser.getUnarrivedParties()); 
        System.out.printf("********************
");

13. Put the thread to sleep for 1 second and close the loop and the class:

              TimeUnit.SECONDS.sleep(1); 
            } 
          } 
        }