Abstract classes vs. interfaces vs. mixins

Question

Could someone please explain to me the differences between abstract classes, interfaces, and mixins? I\'ve used each before in

Answer 1

Reference to Java and given example of Abstract class to provide mixin is misleading. First of all, Java does not support "mixins" by default. In Java terms abstract class and Mixins become confusing.

A mixin is a type that a class can implement in addition to its "primary type" to indicate that it provides some optional behavior. To speak in Java terms, one example would be your business value object implementing Serializable.

Josh Bloch says - "Abstract classes can not be used to define mixins - since a class can not have more than one parent" ( Remember Java allows only one "extends" candidate)

Look for languages like Scala and Ruby for appropriate implementation of the notion of "mixin"