1. onErrorReturn: Observable.just(1, 2, 3, 4) .map(integer -> 10 / integer) .onErrorReturn(throwable -> -1) .subscribe(integer -> Log.d(TAG, "onNext: " + integer)); 2. onErrorResumeNext: Observable.just(1, 2, 3, 4) .map(integer -> 10 / integer) .onErrorResumeNext(Observable.just(-1, -2, -3)) .subscribe(integer -> Log.d(TAG, "onNext: " + integer)); 1. onError: Observable.just(1, 2, 3, 4) .map(integer -> 10 / integer) .subscribe( integer -> Log.d(TAG, "onNext: " + integer), throwable -> Log.e(TAG, "onError: " + throwable.getMessage()) ); 2. retry: Observable.just(1, 2, 3, 4) .map(integer -> 10 / integer) .retry(2) .subscribe(integer -> Log.d(TAG, "onNext: " + integer)); groovy dependencies { implementation 'io.reactivex.rxjava2:rxandroid:2.1.1' }