What Kind Programming Language Used in File on /system/xbin?
You are looking at binary compiled file in the 'ELF' format.

From:
https://en.wikipedia.org/wiki/Executable_and_Linkable_Format


  Android uses ELF .so (shared object) libraries for the Java Native Interface. With Android Runtime (ART), the default since Android 5.0 "Lollipop", all applications are compiled into native ELF binaries on installation.


So that code could have been written in any number of languages.