This is an interface to R for J64 on Windows/Mac/Linux.
J loads a shared library to call R installed on the same machine.
Either R should be on the path, or the R_HOME environment variable should be set when calling J, as in:
SET R_HOME="c:\Program Files\R\R-3.3.2" windows export R_HOME=/usr/lib/R linux
The shared libraries are distributed in ~addons/stats/r/lib with source in the Public repository at stats/r/rserver/lib.