WhatIsClosure - Java Domain Wiki of Yoon Kyung Koo

This is a notion out of the Lisp world that says if you define an anonymous function in a particular lexical context, it pretends to run in that context even when it's called outside of the context.
they're one of those aspects of Perl -- like object-oriented programming -- that everyone raves about and you can't really see the big deal until you play around with them and then they just click. In this article, we're going to play around with some closures, in the hope that they'll just click for you.