Core Java Introduction

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P R E F A C E

The field of computer science has witnessed constant changes since the discovery of

simple calculating machine by Charles Babbage. The era is confronting with speed,

accuracy and mind of computer.

Aim of this book is to introduce under graduate and diploma students with core java

programming. Being Object Oriented, Java has certain functionality which makes it

easy to understand when you are already introduced to Object Oriented concepts.

Students of Information Technology and Computer Science are being prepared with

a view to keep our nation on Hi-Tech map of the world. A nation always counts on

his young blood, when this young blood is well educated and having vision to bring

community and a country forward to the hi-tech world.

Now-a-days, the Information Technology Industry is getting a climatic change at

rapid rate. Public as well as private sectors are not far away from these changes. The

usage of new technologies and systems applications of computer is for ease in

storage retrieval and management of information.

Java is a first step to go forward in programming, where you will be able to

understand basic fundamental concepts, which makes easy to make out higher level

programming. Here my efforts are to bring both learners and java closer. While

composing this book, I was very much impressed with tutorials available online; out

of which tutorialspoint.com has been great reference to me, But being lack in many

points and chapters those are covered in curriculum I have to go beyond it, and get

more references to prepare this book.

When we see Gujarat University’s curriculum it has lack of certain basic points of

core java that, I guess, are important to learn for students. Those who are preparing

for only exam they should go through available twelve chapters only. But those who

want to learn more and want to cover all core concepts and points of core java they

should take six bonus chapters too.

This book is divided in to eighteen chapters, out of them twelve are regular chapters

and six are bonus chapters. These chapters are sequenced in the way to give

comprehensive idea of core java. I have tried my best to make this book

self-contained to enable the reader to grab it quickly.

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Acknowledgement

Knowledge in itself is continuous process. It remains fact that words are short for

expressing out deepest gratitude and sincere thanks towards the people who

inspire, guide and encourage during managing, working and completion of

composing this book.

I would like to express deep gratitude and sincere thanks to all my students to

inspire me to compose such a book, Being traditional I may have used available

resources and may have gone through, but when I came across that my students are

not getting all from available resource, It made me prepare such a material that

provide them 100% of their curriculum.

I would like to thanks my parents and my family, for providing me such a nice

environment to carry on my composition. And they have beard all in-convenience

caused by me during this composition without any complain, they have been always

inspiring and encouraged me throughout the process.

I express my thanks to all colleague staff members of Govt. BCA College for their

co-operation and encouragement. Tutorials point has been great reference to me all

the time even before preparing this book. I want to express my deep gratitude to

them for providing such useful resources.

Last but not least I would like to thank my friends, companions and persons who

played an important role in growing our career by providing their constant

co-operation and encouragement throughout my tenure of composition.

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Index

Chapter 1 Java Overview……….……….9

Chapter 2 Java-Basic Syntax……….14

Chapter 3 Java –Basic Operations………35

Chapter 4 Input Methods in Java……….55

Chapter 5 Java-in built Classes………66

Chapter 6 Regular Expressions………..98

Chapter 7 Java-Methods……….107

Chapter 8 Java-Exception handling.……….117

Chapter 9 Object oriented with java………129

Chapter 10 Interface and Package………145

Chapter 11 Java-Multi threading Overview………154

Chapter 12 Java-Applet Basics……….163

---Bonus Chapters---

Bonus Chapter 1 Data Structures………..……175

Bonus Chapter 2 Java Collection Framework………197

Bonus Chapter 3 Java Generics………..203

Bonus Chapter 4 Serialization………..207

Bonus Chapter 5 Networking……..………211

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History of Java:

10 Tools you will need:

10 Environment Set up

10 Setting up the path for windows 2000/XP:

11 Setting up the path for windows 95/98/ME:

11 Setting up the path for Linux, UNIX, Solaris, FreeBSD:

11 Popular Java Editors:

11 OOP and Its Concepts in Java:

12 First Java Program:

14 Basic Syntax:

15 Java Identifiers:

15 Java Modifiers:

16 Java Variables:

16 Java Arrays:

16 Java Enums:

16 Example:

16 Java Keywords:

17 Comments in Java

18 Using Blank Lines:

18 Inheritance:

18 Interfaces:

18 Objects and Classes:

18 Objects in Java:

19 Classes in Java:

19 Constructors:

20 Creating an Object:

20

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Source file declaration rules:

22 Java Package:

23 Import statements:

23 A Simple Case Study:

23 Basic Data Types:

25 Primitive Data Types:

25 byte:

25 short:

25 int:

26 long:

26 float:

26 double:

26 boolean:

27 char:

27 Reference Data Types:

27 Java Literals:

28 Variable Types

29 Local variables :

29 Instance variables :

31 Class/static variables :

32 Java Modifier Types

33 Access Control Modifiers:

33 Non Access Modifiers:

34 The Arithmetic Operators:

35 The Relational Operators:

36 The Bitwise Operators:

37 The Logical Operators:

38 The Assignment Operators:

39 Misc Operators

41

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instanceOf Operator:

42 Precedence of Java Operators:

42 Loops - for, while and do...while

43 The while Loop:

44 The do...while Loop:

45 The for Loop:

46 Enhanced for loop in Java:

47 The break Keyword:

48 The continue Keyword:

48 Java Decision Making

49 The if Statement:

49 The if...else Statement:

50 The if...else if...else Statement:

51 Nested if...else Statement:

52 The switch Statement:

52 JOptionPane

55 JOptionPane Source Code

56 Java JOptionPane Hierarchy

59 JOptionPane Constructor

59 Scanner class

60 Class Constructors

60 Numeric and String Methods

60 Java - Numbers Class:

66 Number Methods:

67 Java - Character Class

69 Escape Sequences:

70 Character Methods:

71 Java - String Class

72 Creating Strings:

72

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Concatenating Strings:

73 Creating Format Strings:

74 String Methods:

74 Java – Arrays

78 Declaring Array Variables:

78 Creating Arrays:

79 Processing Arrays:

80 The foreach Loops:

81 Passing Arrays to Methods:

81 Returning an Array from a Method:

82 The Arrays Class:

82 Java - Date & Time

83 Getting Current Date & Time

84 Date Comparison:

84 Date Formatting using SimpleDateFormat:

85 Simple DateFormat format codes:

85 Date Formatting using printf:

86 Date and Time Conversion Characters:

87 Parsing Strings into Dates:

90 Sleeping for a While:

90 Measuring Elapsed Time:

91 GregorianCalendar Class:

91 Wrapper Class

95 Why do we need wrapper classes in Java?

95 Features of the Java wrapper Classes.

96 How to use wrapper classes in java?

96 Character class methods:

96 List of the primitive types and the corresponding wrapper classes in java

96 methods of the Wrapper class which are used to manipulate the data

97

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Integer Class

97 Capturing Groups:

98 Regular Expression Syntax:

99 Methods of the Matcher Class:

101 Index Methods:

102 Study Methods:

102 Replacement Methods:

103 The start and end Methods:

103 The matches and lookingAt Methods:

104 The replaceFirst and replaceAll Methods:

105 The appendReplacement and appendTail Methods:

105 PatternSyntaxException Class Methods:

106 Creating a Method:

107 Calling a Method:

108 The void Keyword:

109 Passing Parameters by Values:

110 Overloading Methods:

111 The Scope of Variables:

112 Using Command-Line Arguments:

113 The Constructors:

113 Variable Arguments(var-args):

115 The finalize( ) Method:

115 Exception Hierarchy:

117 Exceptions Methods:

118 Catching Exceptions:

119 Multiple catch Blocks:

120 The throws/throw Keywords:

121 The finally Keyword

122 Declaring you own Exception:

123

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Unchecked exceptions

126 How unchecked exceptions differ from regular exceptions

127 What happens when an unchecked exception occurs

127 The simplistic view

127 Java - Inheritance

129 IS-A Relationship:

129 The instanceof Keyword:

131 HAS-A relationship:

131 Kind-Of Relationship

132 Part-Of Relationship

132 Java – Overriding

132 Rules for method overriding:

134 Using the super keyword:

135 Java - Polymorphism

135 Virtual Methods:

136 Java – Abstraction

139 Abstract Class:

139 Extending Abstract Class:

140 Abstract Methods:

142 Java – Encapsulation

143 Benefits of Encapsulation:

144 Java – Interfaces

145 Declaring Interfaces:

146 Implementing Interfaces:

146 Extending Interfaces:

147 Extending Multiple Interfaces:

148 Tagging Interfaces:

148 Java – Packages

149 Creating a package:

149

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The Directory Structure of Packages:

151 Set CLASSPATH System Variable:

153 Life Cycle of a Thread:

154 Thread Priorities:

155 Creating a Thread:

155 Create Thread by Implementing Runnable:

155 Create Thread by Extending Thread:

157 Thread Methods:

158 Major Thread Concepts:

161 Using Multithreading:

162 Life Cycle of an Applet:

163 A "Hello, World" Applet:

164 The Applet CLASS:

165 Invoking an Applet:

166 Getting Applet Parameters:

166 Specifying Applet Parameters:

168 Application Conversion to Applets:

168 Event Handling:

169 Displaying Images:

170 Playing Audio:

171 Using drawstring() Method to draw Strings

172 Using Color method

173 Drawing lines and shapes

173 The Enumeration:

175 The BitSet

176 The Vector

180 The Stack

186 The Dictionary

187 The Map interface

188

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The Properties

194 The Collection Interfaces:

198 The Collection Classes:

198 The Collection Algorithms:

201 How to use an Iterator ?

201 How to use an Comparator ?

201 Summary:

202 Generic Methods:

203 Bounded Type Parameters:

204 Generic Classes:

205 Serializing an Object:

208 Deserializing an Object:

209 Socket Programming:

211 ServerSocket Class Methods:

212 Socket Class Methods:

214 InetAddress Class Methods:

215 Socket Client Example:

216 Socket Server Example:

217 Send a Simple Email:

219 Send an HTML Email:

221 Send Attachment in Email:

223

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Chapter 1 : Java -

Overview

Java programming language was originally developed by Sun Microsystems, which was initiated by James Gosling and released in 1995 as core component of Sun Microsystems.s Java platform (Java 1.0 [J2SE]).

As of December 08 the latest release of the Java Standard Edition is 6 (J2SE). With the advancement of Java and its wide spread popularity, multiple configurations were built to suite various types of platforms. Ex: J2EE for Enterprise Applications, J2ME for Mobile Applications.

Sun Microsystems has renamed the new J2 versions as Java SE, Java EE and Java ME respectively. Java is guaranteed to be Write Once, Run Anywhere Java is:

• Object Oriented : In java everything is an Object. Java can be easily extended since it is based on the Object model.

• Platform independent: Unlike many other programming languages including C and C++ when Java is compiled, it is not compiled into platform specific machine, rather into platform independent byte code. This byte code is distributed over the web and interpreted by virtual Machine (JVM) on whichever platform it is being run.

• Simple :Java is designed to be easy to learn. If you understand the basic concept of OOP java would be easy to master.

• Secure : With Java's secure feature it enables to develop virus-free, tamper-free systems. Authentication techniques are based on public-key encryption.

• Architectural- neutral :Java compiler generates an architecture-neutral object file format which makes the compiled code to be executable on many processors, with the presence Java runtime system.

• Portable :being architectural neutral and having no implementation dependent aspects of the specification makes Java portable. Compiler and Java is written in ANSI C with a clean portability boundary which is a POSIX subset.

• Robust :Java makes an effort to eliminate error prone situations by emphasizing mainly on compile time error checking and runtime checking.

• Multi-threaded : With Java's multi-threaded feature it is possible to write programs that can do many tasks simultaneously. This design feature allows developers to construct smoothly running interactive applications.

• Interpreted :Java byte code is translated on the fly to native machine instructions and is not stored anywhere. The development process is more rapid and analytical since the linking is an incremental and light weight process.

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