var a int = 0

CountDownLatch countDownLatch = new CountDownLatch(params.size());
        try {
            params.forEach(regionNameMapping -> {
                CompletableFuture.runAsync(() -> {
                        Region region = this.getRegionById(regionNameMapping.getRegionId());
 regionNameMapping.getRegionNameConsumer().accept(region.getName());
                        countDownLatch.countDown();
                });
            });
            countDownLatch.await();
        } catch (Exception e) {
            log.error(e.getMessage(), e);
        }

countDownLatch.await();

public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue) {
        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
             Executors.defaultThreadFactory(), defaultHandler);
    }