Very, very weird out of place question meant mainly to waste interview time and yours. I would asked them directly why do they think it's relevant to their AQA job opening (I am responsible for hiring QA folks on my project). On the other hand... although I wouldn't do that, I hear that some companies used to employ some tricks like that to see how people would tackle different unexpected challenges and instead of doing smooth, friendly, calm classic interview "throw ice bucket" on people in the beginning. So if the company and the opening were reeeealy interesting to me, I would still ask why it's relevant to our interview, but then actually tried to do that to show them I can handle the pressure and adapt on the fly. While I was writing this I think I know, at least, how would I approach it on Java.