Use future and countdownlatch to realize multithreading to execute multiple asynchronous tasks, and return results after all tasks are completed

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;

/** *  use Future And CountDownLatch Implement multithreading to execute multiple asynchronous tasks , After all the tasks are completed, the results will be returned  */
public class TestFuture {
    
    public static void main(String[] args) {
    
        TestFuture testFuture = new TestFuture();
        //  The initial number is three tasks 
        int taskCount = 3;
        List<Future<String>> futures = new ArrayList<>(taskCount);
        // CountDownLatch As a decrement counter , A thread completes a task , Counter minus one , Reduced to 0 When, it means that the task has been completed 
        CountDownLatch downLatch = new CountDownLatch(taskCount);

        ExecutorService executorService = new ThreadPoolExecutor
                (taskCount, 5, 5, TimeUnit.SECONDS, new ArrayBlockingQueue<>(10));

        for (int i = 0; i < taskCount; i++) {
    
            //  Start three asynchronous tasks 
            Future<String> future = executorService.submit(testFuture.executeTask(i, downLatch));
            futures.add(future);
        }

        System.out.println("do other things");

        try {
    
            //  stay downLatch Not for 0 when , The main thread will block here 
            downLatch.await();
            executorService.shutdown();
            //  adopt future To get the results 
            List<String> result = testFuture.getFutureResult(futures);
            for (String s : result) {
    
                System.out.println(s);
            }
        } catch (InterruptedException e) {
    
            e.printStackTrace();
        }
    }

    public Callable<String> executeTask(int i, CountDownLatch downLatch) {
    
        return () -> {
    
            Thread.sleep(i * 1000L);
            downLatch.countDown();
            return "Result " + Thread.currentThread().getName();
        };
    }

    public List<String> getFutureResult(List<Future<String>> futures) {
    
        List<String> result = new ArrayList<>(3);
        for (Future<String> future : futures) {
    
            if (future.isDone() && !future.isCancelled()) {
    
                try {
    
                    result.add(future.get());
                } catch (InterruptedException | ExecutionException e) {
    
                    e.printStackTrace();
                }
            }
        }
        return result;
    }
}