After all the modifications we have made, the flow now became much more easy to understand:

Observable.merge(
        createFinancialStockUpdateObservable(yahooService, query, env),
        createTweetStockUpdateObservable(configuration, 
        trackingKeywords, filterQuery)
)
        .compose(bindToLifecycle())
        .subscribeOn(Schedulers.io())
        .doOnError(ErrorHandler.get())
        .observeOn(AndroidSchedulers.mainThread())
        .doOnError(this::showToastErrorNotificationMethod)
        .observeOn(Schedulers.io())
        .doOnNext(this::saveStockUpdate)
        .onExceptionResumeNext(StorIOFactory
        .createLocalDbStockUpdateRetrievalObservable(this))
        .doOnNext(update -> log(update))
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(stockUpdate -> {
            Log.d("APP", "New update " + stockUpdate.getStockSymbol());
            noDataAvailableView.setVisibility(View.GONE);
            stockDataAdapter.add(stockUpdate);
            recyclerView.smoothScrollToPosition(0);
        }, error -> {
            if (stockDataAdapter.getItemCount() == 0) {
                noDataAvailableView.setVisibility(View.VISIBLE);
            }
        });

It still has some unwieldy .doOnNext() and .observeOn() calls, but as we will see in the next section, some of them can be taken care of using Observable Transformations.