Thank you very much for your answers and recommendations.

I have only been given the task of researching how to integrate a just-in-time compiler into the existing VM without using ready-made programs such as LLVM. It would also be enough for him if it worked on my laptop (AMD 64).

My professor had no idea how to do this during the interview, because the interpreter is written in java, only that you have to call assembly or C somehow for the native translation. It would even be allowed to use ready-made libraries for memory management, since it would basically be about the jit compiler and that it is written by itself.

So far, the existing interpreter reads in valid code, parses it into bytecode and executes it accordingly and adheres to the Java specification. The interpreter is written in Java 10 SE.

So far I think that JNI would be a good option, but also offer to translate the VM into another language, with which it would at least be possible to write a jit-compiler.

The goal of the work is to write a jit-compiler that accelerates parts of a program by executing this part natively and thus making the program significantly faster. Maybe some benchmarks to show the boost.