2: Objects- Defining, Creating, and Using
- Page ID
- 15069
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)
After studying this chapter, you will
- Be familiar with using variables to store and manipulate simple data.
- Be familiar with creating and using objects.
- Understand the relationship between classes and objects.
- Understand the difference between objects and data of primitive type.
- Understand the difference between static and and instance elements of a class.
- Be able to understand and design a simple class in Java.
- Understand some of the basic principles of object-oriented programming.
Introduction
This chapter introduces some more of the basic principles of object-oriented programming. We begin by looking at some examples of creating and using objects of type String and Graphics. Then, we examine how user defined classes are used by doing a detailed walk-through of the Riddle class we saw in Chapter 1. We focus on the basic Java language elements involved. By the end of these sections, you should know how to identify the key elements that make up a Java program.
We then present a detailed example of the programming development process by designing a class that models a certain two person game and implements the class. The design is represented using UML notation.