Create Observable using empty method in RxJava

This type of source signals completion immediately upon subscription.

Observable<String> empty = Observable.empty();

empty.subscribe(new DefaultObserver<String>() {
    @Override
    public void onNext(String s) {
        System.out.println("This should never be printed!");
    }

    @Override
    public void onError(Throwable e) {
        System.out.println("Or this!");
    }

    @Override
    public void onComplete() {
        System.out.println("Done will be printed.");
    }
});

References
https://github.com/ReactiveX/RxJava/wiki/Creating-Observables#empty