HotSubscriber.java

// Define your publisher
ConnectableObservable<Integer> integerObservable = Observable.fromIterable(integerList)
    .map(integer -> integer * 2)
    .publish(); 

// Define your subscribers
Disposable subscribe1 = integerObservable
    .map(integer -> integer * 10)
    .subscribe(integer -> System.out.println("From first subscriber: " + integer));

Disposable subscribe2 = integerObservable
    .map(integer -> integer * 100)
    .subscribe(integer -> System.out.println("From second subscriber: " + integer));

//Start publishing simultaneously
integerObservable.connect();