Learning RxJava

When to use Subjects

More likely, you will use Subjects to eagerly subscribe to an unknown number of multiple source Observables and consolidate their emissions as a single Observable. Since Subjects are an Observer, you can pass them to a subscribe() method easily. This can be helpful in modularized code bases where decoupling between Observables and Observers takes place and executing Observable.merge() is not that easy. Here, I use Subject to merge and multicast two Observable interval sources:

import io.reactivex.Observable;import io.reactivex.subjects.PublishSubject;import io.reactivex.subjects.Subject;import java.util.concurrent.TimeUnit;public class Launcher {    public static void main(String[] args) {        Observable<String> source1 =