RxJava doesn't work in Scheduler.io() thread

Question

The problem in that: I have Observable and Subscriber. I try to launch Observable in .io() thread, because it works with files and zip archivers (I won't show the code - is too large), but Observable do nothing!:

Observable<Double> creatingObservable = getCreatingObservable(image);
Subscriber<Double> creatingSubscriber = getCreatingSubscriber();

creatingObservable
        .subscribeOn(Schedulers.io())
        .subscribe(creatingSubscriber);

If I launch code without the subscribeOn() - all work. What is the problem and how to solve it

P.S. System.out.println() doesn't work too. Problem have all Scheduler's threads.

Answer 1

It seems the problem is that the main thread terminated before creatingObservable could emit any values.

The simple solution: make the main thread wait long enough to enable creatingObservable to emit/complete.

Observable<Double> creatingObservable = getCreatingObservable(image);
Subscriber<Double> creatingSubscriber = getCreatingSubscriber();

creatingObservable
        .subscribeOn(Schedulers.io())
        .subscribe(creatingSubscriber);

Thread.sleep(5000); //to wait 5 seconds while creatingObservable is running on IO thread