github/linguist — pull request #705 by glts (2013-09-30 19:26:11+00:00)
Title: Added J to languages

https://en.wikipedia.org/wiki/J_(programming_language)
http://www.jsoftware.com/

This is a trivial change, please let me know if you require a test for this.

J is not too rare a language on GitHub: Searching for "extension:ijs" gives 3535 matching files.

Thanks.