None of those are a necessity, and they can be easily implemented in an additional layer (e.g. annotation processor if you really wanted to).

No language features above machine code are a "necessity". Java is not a "necessity". "OOP" is not a "necessity" either. Why don't we all work in C? Or maybe all in assembly language? Yet most of us are glad we can work at a higher level. Probably no single language feature is a "necessity", yet when they come together they make for higher level languages and elegant expression.

Hopefully never. There's a reason no primarily functional language ever became mainstream. The "elegant code" they allow is never as lovely as the zealots imagine