Yes, but so does run-time generics somewhere along the line.
Really? AFAIK, compiler creates those functions/classes from corresponding generics (it is called templates in C++, and it really acts like template in C++). Hence, they are compile time.
Well, yes, compile-time generics are compile-time. That's why I said "runtime".
Yes, but you are recommending he do that in Go, so by having an extra array lookup you'd be further slowing down the Go program, which he says is 5x slower than the Java program already.