Ivor Horton's Beginning Java™ 2, JDK™ 5th Edition

Chapter 5. Defining Classes

In this chapter you'll explore the heart of the Java language—classes. Classes specify the objects you use in object-oriented programming. These form the basic building blocks of any Java program, as you saw in Chapter 1. Every program in Java involves classes, since the code for a program can appear only within a class definition.

You'll be exploring the details of how a class definition is put together, how to create your own classes, and how to use classes to solve your own computing problems. And in the next chapter, you'll build on this to look at how object-oriented programming helps you work with sets of related classes.

By the end of this chapter you will have learned:

• What a class is, and how you define a class

• How to implement class constructors

• How to define class methods

• What method overloading is

• What a recursive method is and how it works

• How to create objects of a class type

• What packages are and how you can create and use them

• What access attributes are and how you should use them in your class definitions

• What nested classes are and how you use them

• When you should add the finalize() method to a class

• What native methods are