Introduction to Objects

Abstract

In this chapter, we will explain the following:

• What is a class, an object, a field, and a method

• That an object variable does not hold an object but, rather, a pointer (or reference) to where the object is actually located

• The distinction between a class variable (also called a static variable) and an instance variable (also called a non-static variable)

• The distinction between a class method (also called a static method) and an instance method (also called a non-static method)

• What the access modifiers public, private, and protected mean

• What is meant by information hiding

• How to refer to class and instance variables

• How to initialize class and instance variables

• What is a constructor and how to write one

• What is meant by overloading

• What is meant by data encapsulation

• How to write accessor and mutator methods

• How to print an object’s data in various ways

• Why the tostring() method is special in Java

• What happens when we assign an object variable to another

• What it means to compare one object variable with another

• How to compare the contents of two objects

• How a function can return more than one value using an object