[jrimbault]

Optional ? But redoing the standard lib would be no go in javaland ? It's the non nullable reference I find interesting.

[ComputerGuru]

The API hasn’t changed, and remains backwards compatible. However it has been annotated, so that when targeting it with a compiler configured to validate/verify nullability you get a better (read: safer) experience. It can configured as an error or a warning.

MS does this sort of thing a good amount, preserving backwards compatibility but enhancing the experience.