The reaction here is indicative of why I'm starting to consider whether maybe it's best that Java stays Java. Sure, I'd personally be really annoyed typing super redundant type declarations everywhere. But then again, I wouldn't have to, because I'd simply use Scala, because it's more expressive. But a lot of people clearly love good old verbose Java.

Java has been super slow to adopt things that are more or less the norm in other popular languages. Why bother at this point? Isn't Kotlin a pretty good sugared-up Java, anyway?

Lightbend (caretakers of Scala, Play Framework, Akka, Spark, Slick, SBT, and others) wisely announced their dedication to both Scala and Java. It's caused a big stir in the community, but it kind of seems like that should make everybody happy. They're two ecosystems geared to serious software, built on a solid platform, but with very different constituencies. Lightbend realized there's no point in pressuring people to adopt Scala. People will do it on their own, if they want to. But with strong support of both languages, they can address a very broad swath of the development world.