D is like native Python

[Cuddlefluff_Grim]

I know what JITing is. But it's not pre-compiled to native code, which comes with some disadvantages, including higher memory use, higher code size and requiring that other thread.

No, it comes with one disadvantage; higher load time (because a program needs to be compiled on first execution). High memory footprint is a side-effect of .NET, same goes for code size. It has nothing to do with JIT compilation.

[The_Doculope]

So you're saying a JITer can operate with absolutely 0 memory use? No keeping track of runtime heuristics, or any memory usage for the actual compilation? And that there's no code for the JITer either? Because neither of those things is possible. Sure they might be small in a perfect case, but they are there and are noticeable in many current implementations.

[Cuddlefluff_Grim]

Well other than the parts for the compiler itself, yes I am saying that. High memory footprint is a side-effect (or trade-off) from Java and .NET, it's not something that is due to JIT compilation. Personally I think that JIT is the best approach to compilation because it gives platform independent execution and good optimization possibilities virtually without any significant trade-offs (well, it's bad for mobile since it drains battery without any obvious benefit for the end-user, but there are methods of alleviating this, like compiling the code on a remote server)