CountDownLatchDemo

CountDownLatchDemo.java

import java.util.concurrent.CountDownLatch;

public class CountDownLatchDemo {
    public static void main(String[] args) {
        final CountDownLatch gate = new CountDownLatch(3);

        Thread t1 = new Thread(){
            public void run() {
                try {
                    Thread.sleep(3000);
                    System.out.println("Redis is ready...");
                } catch (InterruptedException ignores) { 
                    //
                }finally {
                    gate.countDown();
                }
            }
        };

        t1.start();

        Thread t2 = new Thread() {
            public void run() {
                try {
                    Thread.sleep(2000);
                    System.out.println("Mysql is ready...");
                } catch (InterruptedException ignores){
                    //
                } finally {
                    gate.countDown();
                }
            }
        };

        t2.start();

        Thread t3 = new Thread() {
            public void run() {
                try {
                    Thread.sleep(1000);
                    System.out.println("RabbitMQ is ready...");
                } catch (InterruptedException ignores){

                } finally {
                    gate.countDown();
                }
            }
        };

        t3.start();

        try {
            gate.await();
        } catch (InterruptedException ignores) { }
        System.out.println("All resources is ready!");
    }
}