Understanding the Y Combinator using Java (2009)

Whenever someone asks me what a Y combinator is, I tell them it is basically like a Klein bottle -- that's the closest analogy I've found. Of course, then they ask me what a Klein bottle is. After explaining that, they look at me weird.

Here is an example using the ycombinator to transparently add memoization to a function. This enables you to get the performance boost of dynamic programming in java without having to rewrite recursion as iteration. (The code uses jdk8 but could be done without it).

http://pastebin.com/as5xcWXp