> very,very high performance if you really need it

But not as high performance as Java directly. And typically not as high performance as native languages, which the author addresses.

There's absolutely nothing about native languages that makes them a-priori faster than the JVM. On the contrary, the JVMs compiler is likely to emit betteroptimized machine code than their compilers. Some low-level languages (like C/C++/Rust) can (and do in many cases) offer better performance, but that's not because they're "native" but because they allow (and require) finer control over every operation. This level of control comes at a significant cost, though.

Notice I said "typically" because, typically it is true that a native language runs faster than Clojure, which is what my comment was referring to.

What clojure and even scala do with the JVM scares me. The most concrete example I know of is using objects for everything. 1 of the fundamental problems I have with many of the higher level JVM languages is how much they hide from you. That being said, most people won't notice. I do numerical software in java so might be a bit more sensitive to some of this stuff.

If you ever have the need, checkout this blog post about optimizing math operations in Clojure http://insideclojure.org/2014/12/15/warn-on-boxed/