ExecutorService's shutdown() doesn't wait until all threads will be finished

Question

I have a code where 4 threads run at the same time. I want to wait until all these 4 threads will be finished. And only after that to continue the app flow.

I tried

Answer 1

Thanks to @Adam Siemion suggestions, here is a final code:

ExecutorService service = Executors.newFixedThreadPool(cpuCoresNum);

int itNum = 1;

for (int i = 0; i < cpuCoresNum; i++) {

    int treadID = itNum++;

    service.submit(() -> {
        Thread.currentThread().setName("Thread_#" + treadID);
        try {
            foo();
        } catch (Exception e) {
            e.printStackTrace();
        }
    });
}

// wait until all threads will be finished
service.shutdown();
try {
    service.awaitTermination(Long.MAX_VALUE, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
    e.printStackTrace();
}