CyclingBarrierExample.java

package com.example.demo;

import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;

public class CyclingBarrierExample {

    private static final CyclicBarrier BARRIER = new CyclicBarrier(3, new FerryBoat());

    public static void main(String[] args) throws InterruptedException {
        for (int i = 1; i <= 9; i++) {
            new Car(i).start();
            Thread.sleep(600L);
        }
    }

    static class FerryBoat implements Runnable {

        @Override
        public void run() {
            try {
                Thread.sleep(500L);
                System.out.println("... Ferry transferring ...");
            } catch (InterruptedException ignored) {
            }
        }
    }

    static class Car extends Thread {

        private int number;

        Car(int number) {
            this.number = number;
        }

        @Override
        public void run() {
            System.out.println(number + " car is ready to transfer");
            try {
                BARRIER.await();
            } catch (InterruptedException | BrokenBarrierException ignored) {
            }
            System.out.println(number + " car is successfully transferred");
        }
    }
}