Introduction to java

Object Oriented
Programming in JAVA

Introduction
• Welcome to the course Object Oriented
Programming in JAVA. This course will cover a
core set of computer science concepts needed
to create a modern software application using
Java.
Object Oriented Programming using JAVA 2

Course Objectives
On completion of this course we will be able to:
1. Identify the importance of Java .
2. Identify the additional features of Java compared to C++ .
3. Identify the difference between Compiler and Interpreter .
4. Identify the difference between applet and application .
5. Apply Object Oriented Principles of Encapsulations, Data
abstraction, Inheritance, Polymorphism.
6. Program using java API (Application Programming Interface).
7. Program using Exception Handling, Files and Threads .
8. Program Using applets and swings .

Course Syllabus
UNIT CONCEPTS to be covered
UNIT-I JAVA Basics
UNIT-II Inheritance
UNIT-III Data structures creation and manipulation in java
UNIT-IV Exception Handling
UNIT-V GUI Programming With JAVA

Why Java is Important
• Two reasons :
– Trouble with C/C++ language is that they are not
portable and are not platform independent
languages.
– Emergence of World Wide Web, which demanded
portable programs
• Portability and security necessitated the
invention of Java

History
• James Gosling - Sun Microsystems
• Co founder – Vinod Khosla
• Oak - Java, May 20, 1995, Sun World
• JDK Evolutions
– JDK 1.0 (January 23, 1996)
– JDK 1.1 (February 19, 1997)
– J2SE 1.2 (December 8, 1998)
– J2SE 1.3 (May 8, 2000)
– J2SE 1.4 (February 6, 2002)
– J2SE 5.0 (September 30, 2004)
– Java SE 6 (December 11, 2006)
– Java SE 7 (July 28, 2011)

Cont..
• Java Editions.
J2SE(Java 2 Standard Edition) - to develop client-
side standalone applications or applets.
J2ME(Java 2 Micro Edition ) - to develop
applications for mobile devices such as cell
phones.
J2EE(Java 2 Enterprise Edition ) - to develop
server-side applications such as Java servlets
and Java ServerPages.

What is java?
• A general-purpose object-oriented language.
• Write Once Run Anywhere (WORA).
• Designed for easy Web/Internet applications.
• Widespread acceptance.

How is Java different from C…
• C Language:
– Major difference is that C is a structure oriented language and
Java is an object oriented language and has mechanism to
define classes and objects.
– Java does not support an explicit pointer type
– Java does not have preprocessor, so we cant use #define,
#include and #ifdef statements.
– Java does not include structures, unions and enum data types.
– Java does not include keywords like goto, sizeof and typedef.
– Java adds labeled break and continue statements.
– Java adds many features required for object oriented
programming.

How is Java different from C++…
• C++ language
Features removed in java:
Java doesn’t support pointers to avoid unauthorized access
of memory locations.
Java does not include structures, unions and enum data
types.
Java does not support operator over loading.
Preprocessor plays less important role in C++ and so
eliminated entirely in java.
Java does not perform automatic type conversions that
result in loss of precision.

Cont…
 Java does not support global variables. Every method
and variable is declared within a class and forms part of
that class.
 Java does not allow default arguments.
 Java does not support inheritance of multiple super
classes by a sub class (i.e., multiple inheritance). This is
accomplished by using ‘interface’ concept.
 It is not possible to declare unsigned integers in java.
 In java objects are passed by reference only. In C++
objects may be passed by value or reference.

Cont …
New features added in Java:
 Multithreading, that allows two or more pieces of the
same program to execute concurrently.
 C++ has a set of library functions that use a common
header file. But java replaces it with its own set of API
classes.
 It adds packages and interfaces.
 Java supports automatic garbage collection.
 break and continue statements have been enhanced in
java to accept labels as targets.
 The use of unicode characters ensures portability.

Cont …
Features that differ:
 Though C++ and java supports Boolean data type, C++ takes
any nonzero value as true and zero as false. True and false in
java are predefined literals that are values for a boolean
expression.
 Java has replaced the destructor function with a finalize()
function.
 C++ supports exception handling that is similar to java's.
However, in C++ there is no requirement that a thrown
exception be caught.

Characteristics of Java
• Java is simple
• Java is object-oriented
• Java is distributed
• Java is interpreted
• Java is robust
• Java is architecture-neutral
• Java is portable
• Java’s performance
• Java is multithreaded
• Java is dynamic
• Java is secure

Java Environment
• Java includes many development tools, classes and
methods
– Development tools are part of Java Development Kit (JDK) and
– The classes and methods are part of Java Standard Library (JSL),
also known as Application Programming Interface (API).
• JDK constitutes of tools like java compiler, java
interpreter and many.
• API includes hundreds of classes and methods grouped
into several packages according to their functionality.

Java is architecture-neutral
JAVA Program Execution

WORA(Write Once Run Anywhere)

Editplus for Java Programming
• Edit Plus Software :
• EditPlus is a 32-bit text editor for the
Microsoft Windows operating system.
• The editor contains tools for programmers,
including syntax highlighting (and support for
custom syntax files), file type conversions, line
ending conversion (between Linux, Windows
and Mac styles), regular expressions for
search-and-replace, spell check etc).

Hello world Program in java

Execution of Hello world Program

Introduction to java

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