RxJava Fanout with network request

Main.java

public static void main(String[] args) {
        int threadCount = Runtime.getRuntime().availableProcessors();
        System.out.println("Thread Count:" + threadCount);

        ExecutorService executorService = Executors.newFixedThreadPool(threadCount);
        Scheduler scheduler = Schedulers.from(executorService);

        Observable.fromArray(buildNetworkUriCalls("oi").toArray())
                .flatMap(url -> getNetworkFutureAndObservable(url)
                        .subscribeOn(scheduler)
                        .map(s -> {
                            System.out.println(Thread.currentThread().getName() + " | " + s);
                            return s;
                        }).map(s -> {
                            System.out.println("insede thread: " + s);
                            return s;
                        }))
                .doOnComplete(executorService::shutdown)
                .subscribe(System.out::println);//Shutdown the threads.



    }

    public static List<String> buildNetworkUriCalls(String z) {
        List<String> obs = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            final String s = z + "-11-" + i;
            obs.add(s);
        }
        return obs;
    }

    public static Observable getNetworkObservsable(Object s) {
        return Observable.just("url -> : " + s);
    }

    public static Observable getNetworkFutureAndObservable(Object s) {
        return Observable.fromFuture(CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "url -> : " + s;
        }));
    }

    public static CompletableFuture getNetwork(Object s) {
        return CompletableFuture.supplyAsync(() -> "url -> : " + s);
    }