How to use Observable.fromCallable() with a checked Exception?

Question

Observable.fromCallable() is great for converting a single function into an Observable. But how do you handle checked exceptions that might be thrown by the functio

Answer 1

Rather than using a Func0 with Observable.fromCallable(), use Callable. For example:

Observable.fromCallable(new Callable() {
    @Override
    public File call() throws Exception {
        return downloadFileFromNetwork();
    }
}

Since Callable's method call() throws Exception, you don't have to wrap your function in a try-catch! This must be what the lambda is using under the hood.