IntroJB01.pdf

Part I: Fundamentals of Programming

By now you have heard a lot about Java and are anxious to

start writing Java programs. The first part of the book is a

stepping stone that will prepare you to embark on the

journey of learning Java. You will begin to know Java and

will develop fundamental programming skills. Specifically,

you will learn how to write simple Java programs with

primitive data types, control statements, methods, and

arrays.

Chapter 1 Introduction to Java and JBuilder 4

Chapter 2 Primitive Data Types and Operations

Chapter 3 Control Statements

Chapter 4 Methods

Chapter 5 Arrays

Introduction to Java and JBuilder 4

Objectives

•

Learn about Java and its history.

• Understand the relationship between Java and the

World Wide Web.

•

Become familiar with JBuilder 4.

•

Create Java projects, compile and run Java programs

with JBuilder 4.

•

Understand Java runtime environment.

•

Write a simple Java application.

Introduction

By now you have heard quite a lot about the exciting Java

programming language. It must seem as if Java is everywhere!

Your local bookstores are filled with Java books. There are

articles about Java in every major newspaper and magazine.

It is impossible to read a computer magazine without coming

across the magic word Java . You must be wondering why Java

is so hot. The answer is that it enables users to deploy

applications on the Internet. In fact, this is its main

distinguishing characteristic. The future of computing will

be profoundly influenced by the Internet, and Java promises

to remain a big part of that future. Java is the Internet

programming language.

You are about to begin an exciting journey, learning a

powerful programming language. Java is cross-platform,

object-oriented, network-based, and multimedia-ready. After

its inception in May 1995, Java quickly became an attractive

language for developing Internet applications. This chapter

introduces Java and its programming features, followed by a

simple example of Java applications.

The History of Java

Java was developed by a team led by James Gosling at Sun

Microsystems, a company best known for its Sun workstations.

Originally called Oak , it was designed in 1991 for use in

embedded consumer electronic applications. In 1995, renamed

Java , it was redesigned for developing Internet

applications. Java programs can be embedded in HTML pages

and downloaded by Web browsers to bring live animation and

interaction to Web clients.

The power of Java is not limited to Web applications, for it

is a general-purpose programming language. It has full

programming features and can be used to develop standalone

applications. Java is inherently object-oriented. Although

many object-oriented languages began strictly as procedural

languages, Java was designed from the start to be object-

oriented. Object-oriented programming (OOP) is a popular

programming approach that is replacing traditional

procedural programming techniques.

NOTE: One of the central issues in software

development is how to reuse code. Object-

oriented programming provides great flexibility,

modularity, clarity, and reusability through

method abstraction, class abstraction, and class

inheritance—all of which you’ll learn about in

this book.

Characteristics of Java

Java has gained enormous popularity. Java's rapid rise and

wide acceptance can be traced to its design and programming

features, particularly its promise that you can write a

program once and run the program anywhere. As stated in the

Java-language white paper by Sun, Java is simple , object-

oriented , distributed , interpreted , robust , secure ,

architecture-neutral , portable , high-performance ,

multithreaded , and dynamic . Let’s analyze these often-used

buzzwords.

Java Is Simple

No language is simple, but Java is a bit easier than the

popular object-oriented programming language C++, which was

the dominant software-development language before Java. Java

is partially modeled on C++, but greatly simplified and

improved. For instance, pointers and multiple inheritance

often make programming complicated. Java replaces the

multiple inheritance in C++ with a simple language construct

called an interface , and eliminates pointers.

Java uses automatic memory allocation and garbage

collection, whereas C++ requires the programmer to allocate

memory and collect garbage. Also, the number of language

constructs is small for such a powerful language. The clean

syntax makes Java programs easy to write and read. Some

people refer to Java as "C++--" because it is like C++, but

with more functionality and fewer negative aspects.

Java Is Object-Oriented

Computer programs are instructions to the computers. You

tell a computer what to do through programs. Without

programs, a computer is an empty machine. Computers do not

understand human languages, so you need to use computer

languages to communicate with computers. There are over one

hundred programming languages. The most popular languages

are:

COBOL (COmmon Business Oriented Language)

FORTRAN (FORmula TRANslation)

BASIC (Beginner All-purpose Symbolic Instructional

Code)

Pascal (Named for Blaise Pascal)

Ada (Named for Ada Lovelace)

C (Whose developer designed B first)

Visual Basic (Basic-like visual language developed by

Microsoft)

Delphi (Pascal-like visual language developed by

Borland)

C++ (an object-oriented language, based on C)

Each language was designed with a specific purpose. COBOL

was designed for business applications and now is used

primarily for business data processing. FORTRAN was designed

for mathematical computations and is used mainly for numeric

computations. BASIC, as its name suggests, was designed to

be learned and used easily. Pascal was designed to as a

simple structural programming language. Ada was developed at

the direction of the Department of Defense, and is mainly

used in defense projects. C is popular among system software

projects like writing compilers and operating systems.

Visual Basic and Delphi are for rapid application

development. C++ is the C language with object-oriented

features.

All of these languages except C++ are known as procedural

programming languages . Software systems developed using

procedural programming languages are based on the paradigm

of procedures. Object-oriented programming models the real

world in terms of objects. Everything in the world can be

modeled as an object. A circle is an object, a person is an

object, and a window’s icon is an object. Even a mortgage

can be perceived as an object. A Java program is object-

oriented because programming in Java is centered on creating

objects, manipulating objects, and making objects work

together.

Part I, “Fundamentals of Programming,” introduces primitive

data types and operations, control statements, methods, and

arrays. These are the fundamentals for all programming

languages. You will learn object-oriented programming in

Part II, “Object-Oriented Programming.” Object-oriented

programming provides great flexibility, modularity, and

reusability. For years, object-oriented technology was

perceived as elitist, requiring a substantial investment in

training and infrastructure. Java has helped object-oriented

technology enter the mainstream of computing. Its simple,

clean syntax makes programs easy to write and read. Java

programs are quite expressive in terms of designing and

developing applications.

Java Is Distributed

Distributed computing involves several computers working

together on a network. Java is designed to make distributed

computing easy. Since networking capability is inherently

integrated into Java, writing network programs is like

sending and receiving data to and from a file. For example,

Figure 1.1 shows three programs running on three different

systems; the three programs communicate with each other to

perform a joint task.

***Insert Figure 1.1 (Same as Figure 1.1 in the 3 rd Edition,

p6)

Figure 1.1

Java programs can run on different systems that work

together.

Java Is Interpreted

You need an interpreter to run Java programs. The programs

are compiled into Java Virtual Machine code called bytecode .

The bytecode is machine-independent and can run on any

machine that has a Java interpreter, as shown in Figure 1.2.

***Insert Figure 1.2 (Same as Figure 1.2 in the 3 rd Edition,

p7)

Figure 1.2

The Java interpreter executes Java bytecode.

Usually, a compiler, such as a C++ compiler, translates a

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