What Kind Programming Language Used in File on /system/xbin? i was explore file in xbin folder, then i found that the file is have strange language like this : 

ELF(   4�Q4   (444  TTT�&gt;�&gt;�M�]�],�LNL^L^hhh88Q�tdpH1H11��R�td�M�]�],,/system/bin/linker


And every each file, always start with :

ELF


so what kind of program is this ? are those code has been compiled before ?
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.