Which JVM based script language use "when" as branch control keyword (instead of "if")?

Question

I saw a presentation with a code-snippet with "when" instead of "if". The code saw like a JVM-based scripting language, used indentation instead of "{}" and not each line was finished with ';'

Could you give me a clue, which language it could be?

Answer 1

Ruby had the case-when statements. My guess would be "JRuby".

case x
when User === x 
    puts "Constant"
when "User" === x
    puts "string"
else 
    puts "nothing"
end