RXTest.java

public class RXTest {

    public static void main(String[] args){

        ExecutorService oneExecutor = Executors.newSingleThreadExecutor();
        ExecutorService twoExecutor = Executors.newSingleThreadExecutor();
        ExecutorService threeExecutor = Executors.newSingleThreadExecutor();

        Scheduler one = Schedulers.from(oneExecutor);
        Scheduler two = Schedulers.from(twoExecutor);
        Scheduler three = Schedulers.from(threeExecutor);

        createObservable()
                .map(createFunction("Function 1"))
                .subscribeOn(one)
                .map(createFunction("Fuction 2"))
                .observeOn(two)
                .map(createFunction("Fuction 3"))
                .observeOn(three)
                .subscribe(createSubscriber());

        System.out.println("Finished!");
        
        /*
        Outputs:
        Finished!
        subscriber : pool-1-thread-1
        Function 1 : pool-1-thread-1
        Fuction 2 : pool-1-thread-1
        Fuction 3 : pool-2-thread-1
        Action : pool-3-thread-1
        */
    }

    private static Observable<String> createObservable() {
        return Observable.create(new Observable.OnSubscribe<String>() {
            public void call(Subscriber<? super String> subscriber) {
                work("subscriber");
                subscriber.onNext("test");
                subscriber.onCompleted();
            }
        });
    }

    private static Action1<String> createSubscriber() {
        return new Action1<String>() {
            public void call(String s) {
                work("Action");
            }
        };
    }

    public static void work(String name){
        try {
            Thread.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(name + " : " + Thread.currentThread().getName());
    }

    public static Func1<String, String> createFunction(final String name){
        return new Func1<String, String>() {
            public String call(String s) {
                work(name);
                return s;
            }
        };
    }
}