Countdown latch count is not getting decremented for nested executor service

Question

I have a class as below :

public class GrpcApiRunnable implements Runnable{

        private final int noOfThreads;
        private final long duration;
        private final CountDownLatch countDownLatch;

        @Override
        public void run() {
      

            ExecutorService executorService = Executors.newFixedThreadPool(noOfThreads);

            long serviceStartTime = System.currentTimeMillis();
            long serviceEndTime = serviceStartTime + duration;

            while(System.currentTimeMillis()<serviceEndTime) {
                executorService.submit(() -> {
                    //do something
                });
            }

            //Wait for all the threads to complete till the specified duration
            awaitTerminationAfterShutdown(executorService,duration);
            countDownLatch.countDown();
        }
    }

I want to call the runnable as below:

public JsonObject performanceTestV21(long duration, int noOfThreads) throws InterruptedException {

        ExecutorService outerExecutorService = Executors.newFixedThreadPool(getGrpcTestInfos().size());
        CountDownLatch countDownLatch = new CountDownLatch(getGrpcTestInfos().size());
        for (GrpcTestInfo grpcTestInfo : getGrpcTestInfos()) {

            outerExecutorService.submit(new GrpcApiRunnable(noOfThreads,duration,countDownLatch));
        }

        countDownLatch.await();
        return new JsonObject(performanceMatrix);
    }

Looks like the countDownLatch count is not getting decremented. The outerExecutorService will create a threadpool of size 23 in my case and I want to wait until all the threads inside the runnable is complete. Where is the mistake?

Answer 1

Moved the countDown() to finally block. The //do something block was throwing exception and hence countdown was never getting decremented.