Java by API/java.util.concurrent/CountDownLatch

CountDownLatch: await()

   <source lang="java">

import java.util.concurrent.CountDownLatch;

public class Main {

 public static void main(String args[]) {
   CountDownLatch cdl = new CountDownLatch(5);
   new MyThread(cdl);
  
   try {
     cdl.await();
   } catch (InterruptedException exc) {
     System.out.println(exc);
   }
   System.out.println("Done");
 }

}

class MyThread implements Runnable {

 CountDownLatch latch;
  
 MyThread(CountDownLatch c) {
   latch = c;
   new Thread(this).start();
 }
  
 public void run() {
   for(int i = 0; i<5; i++) {
     System.out.println(i);
     latch.countDown(); // decrement count
   }
 }

}

 </source>
   
  
 
  

CountDownLatch: countDown()

   <source lang="java">

import java.util.concurrent.CountDownLatch;

public class Main {

 public static void main(String args[]) {
   CountDownLatch cdl = new CountDownLatch(5);
   new MyThread(cdl);
  
   try {
     cdl.await();
   } catch (InterruptedException exc) {
     System.out.println(exc);
   }
   System.out.println("Done");
 }

}

class MyThread implements Runnable {

 CountDownLatch latch;
  
 MyThread(CountDownLatch c) {
   latch = c;
   new Thread(this).start();
 }
  
 public void run() {
   for(int i = 0; i<5; i++) {
     System.out.println(i);
     latch.countDown(); // decrement count
   }
 }

}

 </source>