Kas zip operaatori kasutamine RxJava-s tagab andmevoogude samaaegse täitmise?

The zip operator in RxJava does not guarantee concurrent (parallel) execution of data streams. It combines elements from multiple Observables, waiting for each to emit its next element, and then merges these elements into one.

Important:

• zip synchronizes streams by elements, meaning it waits until all sources provide an element at the same position.
• Streams can be executed sequentially or in parallel depending on the scheduler, but zip itself does not start them in parallel.

If parallel execution is needed, you must explicitly use the appropriate operators and schedulers, such as subscribeOn(Schedulers.io()).

Example:

Observable<Integer> obs1 = Observable.just(1, 2, 3).subscribeOn(Schedulers.computation());
Observable<String> obs2 = Observable.just("A", "B", "C").subscribeOn(Schedulers.io());

Observable.zip(obs1, obs2, (num, str) -> num + str)
    .subscribe(System.out::println);

Here, streams can run in parallel thanks to subscribeOn, but zip will wait for both to emit their elements before merging.