title: What is the difference between an Abstract Class and a Mixin?
body: <p>I just found an <a href="http://www.infoq.com/news/2008/11/Qi4j" rel="nofollow noreferrer">article</a> on a framework in Java that apparently allows it to support <a href="http://en.wikipedia.org/wiki/Mixin" rel="nofollow noreferrer">Mixins</a> and something called Composite Oriented Programming (which for all I know might even be the same thing...)  I've also heard of/worked with AOP, and I'm not sure how it differs from this either...</p>