Java All-in-One For Dummies, 6th Edition

Chapter 5

Using Abstract Classes and Interfaces

IN THIS CHAPTER

Understanding abstract methods and classes

Using basic interfaces

Using interfaces as types

Adding constants to an interface

Inheriting interfaces

Working with callbacks

Using default methods

In this chapter, you find out how to use two similar but subtly distinct features: abstract classes and interfaces. Both let you declare the signatures of the methods and fields that a class implements separately from the class itself. Abstract classes accomplish this by way of inheritance. Interfaces do it without using inheritance, but the effect is similar. This chapter also covers a feature called default methods, which are designed to make interfaces easier to work with.

Using Abstract Classes

Java lets you declare that a method ...