ZipObservable.java

/*  
 * We create two Observables which emit an item evert second.
 * We combine the two Observables using zip() operator.
 * This combines the result of both operators together so we can
 * perform some modifications to the results and emit them.
 */
Observable<String> alphabets1 = Observable
                .interval(1, TimeUnit.SECONDS).map(id -> "A" + id);

  Observable<String> alphabets2 = Observable
                .interval(1, TimeUnit.SECONDS).map(id -> "B" + id);

  Observable.zip(alphabets1, alphabets2, new BiFunction<String, String, String>() {
            @Override
            public String apply(String s, String s2)  {
                return (s + " " + s2);
            }
             })
                .subscribe(new Observer<String>() {
                    @Override
                    public void onSubscribe(Disposable d) {

                    }

                    @Override
                    public void onNext(String s) {
                        System.out.println("onNext: " + s);
                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onComplete() {

                    }
                });



        Thread.sleep(5000);