MaterializeObservable.java

        Observable.just("A", "B", "C", "D", "E", "F")
                .materialize()
                .subscribe(new Observer<Notification<String>>() {
                    @Override
                    public void onSubscribe(Disposable d) {

                    }

                    @Override
                    public void onNext(Notification<String> stringNotification) {
                        /*
                         * From the notification object, we can check if the
                         * emitted item is:
                         * isOnNext() or isOnError() or isOnComplete()
                         *
                         * Here we can basically fetch items that are successful
                         * & omit items that resulted in error.
                         *
                         *  */
                        System.out.println(stringNotification.getValue());
                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onComplete() {

                    }
                });