On: Official proposal for Type Unions in C#

[tombert]

Most of my jobs until recently have been using Java 11, so I didn’t get to use these things.

[sideeffffect → tombert]

I see. But no hope is lost! You can always lean on Scala. It runs fine on any Java >= 8 and it's great. Unless you intentionally used is badly (but you could say that about any language).