Just Java™ 2

Chapter 11. Interfaces

• What Problem Does an Interface Solve?

• Interface java.lang.Comparable

• Interfaces Versus Abstract Classes

• Granting Permission Through an Interface—Cloneable

• What Protected Really Means

• Using Interface Callbacks for GUI Event Handlers

• The Class Double

• Exercises

• Some Light Relief—The Java-Powered Toaster

Interfaces are an important concept in Java. In this chapter, we'll explain what interfaces do, and how you use them. Here's a summary of what interfaces do, so you can see where we're headed.

In a few words, an interface is similar to a class that only abstract methods. You can't instantiate an abstract class; its purpose is to force any subclasses to implement its methods. That allows other classes to rely ...