private io.reactivex.Single<String> getMyTask() {
        return io.reactivex.Single.fromCallable(new Callable<String>() {
            @Override
            public String call() throws Exception {
                Log.d("ERSEN","Task Started!");
                Random random = new Random(System.currentTimeMillis());

                if(random.nextBoolean()){
                    return "WORK COMPLETED";
                }
                Log.d("ERSEN","Task Had An Error!");
                throw new IllegalArgumentException();
            }
        });
    }

compositeDisposable.add(getMyTask()
                .repeatWhen(new Function<Flowable<Object>, Publisher<?>>() {
                    @Override
                    public Publisher<?> apply(final Flowable<Object> objectFlowable) throws Exception {
                        return objectFlowable.delay(INTERVAL, TimeUnit.SECONDS);
                    }
                })
                .retryWhen(throwableFlowable -> throwableFlowable.flatMap(new Function<Throwable, Publisher<?>>() {
                    @Override
                    public Publisher<?> apply(Throwable throwable) throws Exception {
                        if (throwable instanceof ClassCastException) {
                            return Flowable.error(throwable);
                        }
                        return throwableFlowable.delay(INTERVAL, TimeUnit.SECONDS);
                    }
                }))
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(this::onSuccess, this::onError));

This processor allows only a single Subscriber