Simple RxJava observable example to make a network request.

Observable.java

Observable.fromCallable(() -> {
    Request request = new Request.Builder()
            .url(url)
            .build();
    try {
        Response response = sHttpClient.newCall(request).execute();
        return response.isSuccessful();
    } catch (IOException e) {
        Log.e("Network request", "Failure", e);
    }

    return false;
})
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe((result) -> {
            //Use result for something
        });