How to resume mapping a list if one fails RxJava

Question

Given the following code, the onErrorResumeNext method will just replace an errored item in the list with "hi". How would I go about getting it to continue on with iterating through the rest of the list?

List<Object> list = new ArrayList<>();
list.add("one");
list.add(new Testo());
list.add("two");
list.add("three");    

Observable.fromIterable(list)
    .map(item -> item.toString())
    .onErrorResumeNext(Observable.just("hi"))
    .subscribe(item -> System.out.println(item), onError -> System.out.println("error"));

private static class Testo {
    @Override
    public String toString() {
        throw new NullPointerException();
    }
}

Answer 1

You can add an inner reactive stream, so the outer won't be terminated when error occures:

Observable.fromIterable(list)
    .flatMap((item) -> Observable.just(item)
        .map(_item -> _item.toString())
        .onErrorResumeNext(Observable.just("hi")))
    .subscribe(item -> System.out.println(item), onError -> System.out.println("error"));