CJam is a stack-oriented programming language heavily inspired from GolfScript and suitable for code golfing.
It is an interpreted language, and the official interpreter is written in java.
The name stands for cherry jam. The author is also using the language in Google Code Jam competitions, and included a class called
JamCode that helps deal with the input and output for multiple cases, but otherwise the language is not related to the Code Jam or Google in any way.
In order to run a CJam program, download the latest jar file, e.g. cjam-0.6.5.jar, and run this command:
java -jar cjam-0.6.5.jar file.cjam
You can also launch an interactive shell:
java -cp cjam-0.6.5.jar net.aditsu.cjam.Shell
A browser-based interpreter is available at http://cjam.aditsu.net (it's client-side, works offline after initial loading)