One could call it a language-transfer, but that doesn’t sound very technical. In this specific case I am writing about transferring a program from Java to Python, if that is relevant for the answer.
>Solution :
Transpiling: Taking source code written in one language and transforming into another language that has a similar level of abstraction
More information is available on Wikipedia and in this question: Compiling vs Transpiling
This assumes it’s automatically done. If it’s manually done it is usually referred to as porting.