Java Optional orElseThrow with empty collection

Question

I\'m implementing a stream in which I use a collection listOfFoo to get ids of all items in that list and use them to get values of Bar instances.

Answer 1

I don't really see the benefit of using Optional, it would be more readable without it :

List bars = listOfFoos.stream()
   .map(Foo::getId)       
   .map(service::getBars)                    
   .collect(Collectors.toList());

if (bars.isEmpty()) {
   throw new ResourceNotFoundException(Bar.class, OBJECT_NULL);
}