JIT runtimes usually result in (very) slow first execution, and the post in question is specifically about app launch. Responsiveness is not isolated to only af

JIT runtimes usually result in (very) slow first execution, and the post in question is specifically about app launch. Responsiveness is not isolated to only after the app has been chugging along for a while. > Hell, a hot loop in Java can be as fast as C code Only if the Java code in question is written like C code and not like Java code. Which is sometimes possible, yes, but very very rare, and almost never done. > and it has support for vector instructions as well if you want to write even faster (and platform-independent) code than you could with only C. Absolutely nonsense. C compilers are more than capable of cpu-specific vectorization, too. CPU detection at runtime is ancient technology and perfectly compatible with AOT languages. And since offline compilers have the benefit of getting to spend all the time in the world on it, regularly and consistently have much better auto vectorization outputs. JITs are normally under such a time crunch that it's common for their initial output to be quite mediocre, hence why you end up with multi-level JITs. Which then take even longer before the code stops being slow. Great for benchmarks, but pretty shit in the real world for general app performance. Now you can sometimes have your cake and eat it too here, such as what Google is doing with cloud profiles on Android to basically run the JIT ahead of time. But that is very far from the norm for JIT'd things.