On Second Thought: Interfaces

Continuing my reexamination of past opinions...

Five years ago, and about one month, I wrote that interfaces in Java were essentially useless, mainly because I almost always have a modicum of generic logic I want to have associated with the classes that implement the interface, so I always end up using an abstract class instead. Over the years, however, my tune has changed on that topic, primarily due to my work with Ruby. I've seen the light of duck-typing and mixins and the closest you can get to that in Java is via interfaces rather than inheritance.

So, on second though, interfaces are good.