Rxjava subscribeon, observeon

Observable.just(1) // 1 will be emited in the IO thread pool
          .subscribeOn(Schedulers.io())
          .flatMap(...) // will be in the IO thread pool
          .observeOn(Schedulers.computation())
          .flatMap(...) // will be executed in the computation thread pool
          .observeOn(AndroidSchedulers.mainThread())
          .subscribe(); // will be executed in the Android main thread (if you're running your code on Android)

thread: ReactiveX/RxJava#2925