Sams Teach Yourself Java™ 6 in 21 Days

Chapter 3. Working with Objects

Java is a heavily object-oriented programming language. When you do work in Java, you use objects to get the job done. You create objects, modify them, move them around, change their variables, call their methods, and combine them with other objects. You develop classes, create objects out of those classes, and use them with other classes and objects.

Today, you work extensively with objects. The following topics are covered:

• Creating objects (also called instances)

• Testing and modifying class and instance variables in those objects

• Calling an object’s methods

• Converting objects and other types of data from one class to another

Creating New Objects

When you write a Java program, you define a set of classes. As you learned ...