Data Structures and Algorithms
with Object-Oriented Design Patterns in Java 
A Java interface comprises a set of method prototypes. Different classes can implement the same interface. In this way, Java facilities polymorphism--the idea that a given abstraction can have many different forms. You should understand how interfaces are used together with abstract classes and inheritance to support polymorphism.
Copyright © 1998 by Bruno R. Preiss, P.Eng. All rights reserved.