How to execute observable in parallel threads

Question

I have Observable called messages which contains several messages.I want to process these messages at the same time.How can i do this using rxJava??

messages.(code to execute observable items parallel).subscribe(msg->process(msg))

(If the observable contains five different messages then I need to process these five messages in five seperate threads)

Answer 1

If you want to stay in the Observable world, you can flatMap each element with subscribeOn and computation you want in parallel:

Observable.range(1, 10)
.flatMap(v -> 
    Observable.fromCallable(() -> compute(v))
    .subscribeOn(Schedulers.computation)
)
.subscribe(e -> { }, Throwable::printStackTrace);

Answer 2

Run single thread that "observe" your messages, and dispatch every message that it contains to new message handling task (eg simple Runnable ) that is submitted to some sort of workers thread pool .

Here you will find simple how-to: https://docs.oracle.com/javase/tutorial/essential/concurrency/executors.html