And the run-time of a managed language is 100% able to change all the timing of that if it's smart enough. It provides a guarantee of outcome not of timing. The

And the run-time of a managed language is 100% able to change all the timing of that if it's smart enough. It provides a guarantee of outcome not of timing. There are examples of unexpected optimisations even from static compilers such as gcc (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56888 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56888 for example). There's nothing stopping the jvm from bailing out early even in your second example. If you'd done something like xoring all the bytes together then checking the result then maybe we'd be approaching something that it's unlike a jit could handle, but the code as is seems ripe for a decent optimiser to me. And remember that according to the spec you're now coding for a perfect optimiser, not just a decent one...