, Java
About the Tutorial
Java is a high-level programming language originally developed by Sun Microsystems and
released in 1995. Java runs on a variety of platforms, such as Windows, Mac OS, and the
various versions of UNIX. This tutorial gives a complete understanding of Java.
This reference will take you through simple and practical approaches while learning Java
Programming language.
Audience
This tutorial has been prepared for the beginners to help them understand the basic to
advanced concepts related to Java Programming language.
Prerequisites
Before you start practicing various types of examples given in this reference, we assume
that you are already aware about computer programs and computer programming
languages.
Execute Java Online
For most of the examples given in this tutorial, you will find a ‘Try it’ option, which you
can use to execute your Java programs at the spot and enjoy your learning.
Try following the example using the ‘Try it’ option available at the top right corner of the
following sample code box −
public class MyFirstJavaProgram {
public static void main(String []args) {
System.out.println("Hello World");
}
}
i
, Java
Table of Contents
About the Tutorial ............................................................................................................................................ i
Audience ........................................................................................................................................................... i
Prerequisites ..................................................................................................................................................... i
Execute Java Online .......................................................................................................................................... i
Table of Contents ............................................................................................................................................ ii
JAVA – BASICS ............................................................................................................................. 1
1. Java – Overview ........................................................................................................................................ 2
History of Java ................................................................................................................................................. 3
Tools You Will Need ......................................................................................................................................... 3
Try It Option .................................................................................................................................................... 4
What is Next? .................................................................................................................................................. 4
2. Java - Environment Setup ......................................................................................................................... 5
Try it Option Online ......................................................................................................................................... 5
Local Environment Setup ................................................................................................................................. 5
Popular Java Editors ........................................................................................................................................ 6
What is Next? .................................................................................................................................................. 6
3. Java – Basic Syntax .................................................................................................................................... 7
First Java Program ........................................................................................................................................... 7
Basic Syntax ..................................................................................................................................................... 8
Java Identifiers ................................................................................................................................................. 9
Java Modifiers.................................................................................................................................................. 9
Java Variables .................................................................................................................................................. 9
Java Arrays ....................................................................................................................................................... 9
Java Enums .................................................................................................................................................... 10
Java Keywords ............................................................................................................................................... 10
Comments in Java .......................................................................................................................................... 11
Using Blank Lines ........................................................................................................................................... 12
Inheritance .................................................................................................................................................... 12
Interfaces ....................................................................................................................................................... 12
What is Next? ................................................................................................................................................ 12
4. Java – Objects & Classes.......................................................................................................................... 13
Objects in Java ............................................................................................................................................... 13
Classes in Java ................................................................................................................................................ 14
Constructors .................................................................................................................................................. 14
How to Use Singleton Class? ......................................................................................................................... 15
Creating an Object ......................................................................................................................................... 17
Accessing Instance Variables and Methods................................................................................................... 18
Source File Declaration Rules ........................................................................................................................ 20
Java Package .................................................................................................................................................. 20
Import Statements ........................................................................................................................................ 21
A Simple Case Study ...................................................................................................................................... 21
What is Next? ................................................................................................................................................ 23
ii
, Java
5. Java – Basic Datatypes ............................................................................................................................ 24
Primitive Datatypes ....................................................................................................................................... 24
Reference Datatypes ..................................................................................................................................... 26
Java Literals ................................................................................................................................................... 26
What is Next? ................................................................................................................................................ 28
6. Java – Variable Types .............................................................................................................................. 29
Local Variables ............................................................................................................................................... 29
Instance Variables ......................................................................................................................................... 31
Class/static Variables ..................................................................................................................................... 33
What is Next? ................................................................................................................................................ 34
7. Java – Modifier Types ............................................................................................................................. 35
Java Access Modifiers .................................................................................................................................... 35
Java Non-Access Modifiers ............................................................................................................................ 38
The Static Modifier ........................................................................................................................................ 38
The Final Modifier ......................................................................................................................................... 39
The Abstract Modifier.................................................................................................................................... 41
Access Control Modifiers ............................................................................................................................... 43
Non-Access Modifiers .................................................................................................................................... 44
What is Next? ................................................................................................................................................ 44
8. Java – Basic Operators ............................................................................................................................ 45
The Arithmetic Operators .............................................................................................................................. 45
The Relational Operators............................................................................................................................... 47
The Bitwise Operators ................................................................................................................................... 49
The Logical Operators .................................................................................................................................... 52
The Assignment Operators ............................................................................................................................ 53
Miscellaneous Operators............................................................................................................................... 57
Precedence of Java Operators ....................................................................................................................... 59
What is Next? ................................................................................................................................................ 59
9. Java – Loop Control ................................................................................................................................. 60
While Loop in Java ......................................................................................................................................... 61
for Loop in Java .............................................................................................................................................. 62
Do While Loop in Java ................................................................................................................................... 65
Loop Control Statements ............................................................................................................................... 67
Break Statement in Java ................................................................................................................................ 67
Continue Statement in Java ........................................................................................................................... 69
Enhanced for loop in Java .............................................................................................................................. 70
What is Next? ................................................................................................................................................ 71
10. Java – Decision Making ........................................................................................................................... 72
If Statement in Java ....................................................................................................................................... 73
If-else Statement in Java................................................................................................................................ 74
The if...else if...else Statement ...................................................................................................................... 76
Nested if Statement in Java ........................................................................................................................... 77
Switch Statement in Java ............................................................................................................................... 78
The ? : Operator: ........................................................................................................................................... 80
What is Next? ................................................................................................................................................ 81
iii
About the Tutorial
Java is a high-level programming language originally developed by Sun Microsystems and
released in 1995. Java runs on a variety of platforms, such as Windows, Mac OS, and the
various versions of UNIX. This tutorial gives a complete understanding of Java.
This reference will take you through simple and practical approaches while learning Java
Programming language.
Audience
This tutorial has been prepared for the beginners to help them understand the basic to
advanced concepts related to Java Programming language.
Prerequisites
Before you start practicing various types of examples given in this reference, we assume
that you are already aware about computer programs and computer programming
languages.
Execute Java Online
For most of the examples given in this tutorial, you will find a ‘Try it’ option, which you
can use to execute your Java programs at the spot and enjoy your learning.
Try following the example using the ‘Try it’ option available at the top right corner of the
following sample code box −
public class MyFirstJavaProgram {
public static void main(String []args) {
System.out.println("Hello World");
}
}
i
, Java
Table of Contents
About the Tutorial ............................................................................................................................................ i
Audience ........................................................................................................................................................... i
Prerequisites ..................................................................................................................................................... i
Execute Java Online .......................................................................................................................................... i
Table of Contents ............................................................................................................................................ ii
JAVA – BASICS ............................................................................................................................. 1
1. Java – Overview ........................................................................................................................................ 2
History of Java ................................................................................................................................................. 3
Tools You Will Need ......................................................................................................................................... 3
Try It Option .................................................................................................................................................... 4
What is Next? .................................................................................................................................................. 4
2. Java - Environment Setup ......................................................................................................................... 5
Try it Option Online ......................................................................................................................................... 5
Local Environment Setup ................................................................................................................................. 5
Popular Java Editors ........................................................................................................................................ 6
What is Next? .................................................................................................................................................. 6
3. Java – Basic Syntax .................................................................................................................................... 7
First Java Program ........................................................................................................................................... 7
Basic Syntax ..................................................................................................................................................... 8
Java Identifiers ................................................................................................................................................. 9
Java Modifiers.................................................................................................................................................. 9
Java Variables .................................................................................................................................................. 9
Java Arrays ....................................................................................................................................................... 9
Java Enums .................................................................................................................................................... 10
Java Keywords ............................................................................................................................................... 10
Comments in Java .......................................................................................................................................... 11
Using Blank Lines ........................................................................................................................................... 12
Inheritance .................................................................................................................................................... 12
Interfaces ....................................................................................................................................................... 12
What is Next? ................................................................................................................................................ 12
4. Java – Objects & Classes.......................................................................................................................... 13
Objects in Java ............................................................................................................................................... 13
Classes in Java ................................................................................................................................................ 14
Constructors .................................................................................................................................................. 14
How to Use Singleton Class? ......................................................................................................................... 15
Creating an Object ......................................................................................................................................... 17
Accessing Instance Variables and Methods................................................................................................... 18
Source File Declaration Rules ........................................................................................................................ 20
Java Package .................................................................................................................................................. 20
Import Statements ........................................................................................................................................ 21
A Simple Case Study ...................................................................................................................................... 21
What is Next? ................................................................................................................................................ 23
ii
, Java
5. Java – Basic Datatypes ............................................................................................................................ 24
Primitive Datatypes ....................................................................................................................................... 24
Reference Datatypes ..................................................................................................................................... 26
Java Literals ................................................................................................................................................... 26
What is Next? ................................................................................................................................................ 28
6. Java – Variable Types .............................................................................................................................. 29
Local Variables ............................................................................................................................................... 29
Instance Variables ......................................................................................................................................... 31
Class/static Variables ..................................................................................................................................... 33
What is Next? ................................................................................................................................................ 34
7. Java – Modifier Types ............................................................................................................................. 35
Java Access Modifiers .................................................................................................................................... 35
Java Non-Access Modifiers ............................................................................................................................ 38
The Static Modifier ........................................................................................................................................ 38
The Final Modifier ......................................................................................................................................... 39
The Abstract Modifier.................................................................................................................................... 41
Access Control Modifiers ............................................................................................................................... 43
Non-Access Modifiers .................................................................................................................................... 44
What is Next? ................................................................................................................................................ 44
8. Java – Basic Operators ............................................................................................................................ 45
The Arithmetic Operators .............................................................................................................................. 45
The Relational Operators............................................................................................................................... 47
The Bitwise Operators ................................................................................................................................... 49
The Logical Operators .................................................................................................................................... 52
The Assignment Operators ............................................................................................................................ 53
Miscellaneous Operators............................................................................................................................... 57
Precedence of Java Operators ....................................................................................................................... 59
What is Next? ................................................................................................................................................ 59
9. Java – Loop Control ................................................................................................................................. 60
While Loop in Java ......................................................................................................................................... 61
for Loop in Java .............................................................................................................................................. 62
Do While Loop in Java ................................................................................................................................... 65
Loop Control Statements ............................................................................................................................... 67
Break Statement in Java ................................................................................................................................ 67
Continue Statement in Java ........................................................................................................................... 69
Enhanced for loop in Java .............................................................................................................................. 70
What is Next? ................................................................................................................................................ 71
10. Java – Decision Making ........................................................................................................................... 72
If Statement in Java ....................................................................................................................................... 73
If-else Statement in Java................................................................................................................................ 74
The if...else if...else Statement ...................................................................................................................... 76
Nested if Statement in Java ........................................................................................................................... 77
Switch Statement in Java ............................................................................................................................... 78
The ? : Operator: ........................................................................................................................................... 80
What is Next? ................................................................................................................................................ 81
iii
