yes, but that's just one part of the equation. machine code from compiler and/or language A is not necessarily the same as the machine code from compiler and/or language B. the reasons are, among others, contextual information, handling of undefined behavior and memory access issues.

you can compile many weakly typed high level languages to machine code and their performance will still suck.

java's language design simply prohibits some optimizations that are possible in other languages (and also enables some that aren't in others).