jruby software package provides 100% pure-Java implementation of Ruby, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install jruby
jruby is installed in your system.
Make ensure the jruby package were installed using the commands given below,
$ sudo dpkg-query -l | grep jruby *
You will get with jruby package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Ruby |
| Package | jruby |
| Version | 1.5.6-9 |
| Description | 100% pure-Java implementation of Ruby |
| Sub Section | Ruby |