Alternatively ...
Just produce 400 pages of ALGOL code and ask the lad to implement it in Java, if he tumbles to the fact that the code is something else entirely just say, "Oh it must have been renamed, I'll see if I can find the previous version ... but don't worry, I've still got the flow charts ..." which of course was old faxes and now resemble Egyptian hieroglyphs after being left in the light for 10 years.