I miss all that from C#, some of it a lot. But Java has a community so large that they've basically hacked these things into Java anyways.

LINQ -> streams, QueryDSL, RxJava, JOOQ etc

Async/await -> Comsat/Quasar

The type system is lightyears better in C# but it was rare that I needed those features. Usually you can hack around the limitations and end up with something (slightly cruftier) that does the same thing in Java. Mockito, Retrofit, and RxJava are good examples of hacking about the type system until you have something good enough. That said, there are definitely times I still miss C#'s stellar type system. Easily the best of any language I've touched besides maybe Typescript (which is designed by the same guy)