Introduction to JAVA

Introduction to JAVA

Java J2EE Training

Introduction to Java• Java History• Features of Java• Java Versions• Application Area

Features Of Java

• S i m p l e• O b j e c t - O r i e n t e d• P l a tf o r m

i n d e p e n d e n t• S e c u r e d• R o b u s t• A r c h i t e c t u r e

n e u t r a l• P o r t a b l e• D y n a m i c• I n t e r p r e t e d• H i g h P e r f o r m a n c e• M u l ti t h r e a d e d• D i s t r i b u t e d

History of Java• James Gosling, Mike Sheridan, and Patrick Naughton initiated the Java

language project in June 1991. The small team of sun engineers called Green Team.

• Originally designed for small, embedded systems in electronic appliances like set-top boxes.

• Firstly, it was called "Greentalk" by James Gosling and file extension was .gt.

• After that, it was called Oak and was developed as a part of the Green project.

• Originally developed by James Gosling at Sun Microsystems (which is now a subsidiary of Oracle Corporation)

James Gosling

Features Of Java

• Simple– Similar to C and C++– Omits operator overloading, multiple inheritance– Goto statement is eliminated– Header files are eliminated– Explicit use of pointers– Garbage collection– A rich set of predefined classes

Features Of Java

• Object-Oriented– Forces the programmer to use the classes and object– Class

• Member variables( data ) and member functions ( methods )

Features Of Java

• Robust– designed for writing highly reliable or robust software:– automatic garbage collection, which prevents memory

leaks– Type safety of data– Extensive compile tome and runtime checking– Object Oriented Exception Handling of run time errors• Divide by zero exception.

Features Of Java

• Architectural Neutral and Interpreted– compiler generates bytecodes– Easy to interpret on any machine– “Write once and run anywhere WORA”

Features Of Java

• Powerful– Networking– Threads– Distributed Objects– Database Access– Graphics– Data structure library– Serialization– Digital Signatures

Features Of Java

• Java is Popular

Features Of Java

• Distributed– Supports TCP/IP– RMI– Access remote objects

via URL

Features of Java

• MultiThreaded– Parallel processing

Eg: Winword application saving document every 10 minutes using thread

Major Java Editions

• Standard Edition• Enterprise Edition• Micro Edition

Major Java Editions

• Standard Edition• Applications

– Desktop programing– Applets, Java FX– Big Data Apps

• Examples– MindCraft– Eclipse, Netbeans– GWT

Features Of Java

• Enterprise Edition– Java EE ( formerly J2EE )

• Applications– Servlets, JSP, JSF, PrimeFaces– EJB, Spring and Hibernate

• Examples– Amazon.com– Ebay– Paypal

Features Of Java• Java Micro Edition– Java running on small devices

• Applications– CellPhones,embedded, printers

• Examples– Blackberry, android( optimized java SE )

Java SE VersionsYear Version Platform CodeName Features

1996 1 1.01997 1.1 11998 1.2 2 Playground Swings, Frameworks

2000 1.3 2 Kestrel Assertion, chained exceptions2002 1.4 2 Merlin2004 1.5 5 Tiger Generics, Varargs,

Printf, Enhanced for loop

2006 1.6 6 Mustang Updates to collection and swing

2011 1.7 7 Dolphin Diamond operator, Strings in swichTry-with resources

2014 1.8 8 - Lambda for functional programing,Streams for bulk updates

JDK8• Java development kit– Bundle of software components that are needed to

develop java application – JDK consists • Java Compiler ( javac ) • Java Interpreter (java)• Java debugger• Java applet viewer• Javap

JVM• The JVM is an abstract computing machine• It is responsible for Java's cross-platform portability

JRE• The JRE is the software environment in which programs

compiled for a typical JVM implementation can execute• Implementation of the JVM• Code necessary to run Java programs• dynamically link native methods• manage memory• handle exceptions

JIT ( Just In Time Compiler)

Object Oriented Programing• Object Oriented methodology• Advantages of object oriented approach• Features of Object Oriented approach

Object Oriented Programing• Software development methodology• Maps to real world objects

– Graphics Car Real Cal

• Revolves around objects and classes• Object can communicate with each other• Software is divided into modules• Arranges the object in hierarchy.

Object Oriented Programing• Consists of classes and object.• Object communicates with each other by passing messages

What is an object????

Object Oriented Programing

• Object is an instance of class• Object is an real time entity– State – Behavior– Identity

NotePad Code{

filenameText:readOnly

Open()Close()Minimize()MaxmizeSave()}

Object = Instance Of Notepad

Object StatesAn Object has state and behavior

Objects

• Objects have state and behavior– State: What an object knows about itself– Behavior :What an object can do.

Object Name

State = charecterstics

Behaviour:

DogState: Name Breed Height Weight

Behaviour: eat() run() walk()

Classes

• Collection of objectswheelsSeats

Car Music

GearsA.C

Engine

Class• Class consists of

– Member variables and member methods.– State/ characteristics is represented via member variables– Member methods defines the responsibility of the class– Data within object represents its state.

– Messaging Application • State-> Member Variables

– To: – Text:

• Behaviour – Member functions– sendSms– Forward– delete

Class

• Class is blue print– Logical structure– Set of instructions given to JVM , how to create instance ( object ) out

of it.

Messages

ToText

sendSmsForwardcancel

Messages1: Tom

To : 123-456-7896Text : Hi Tom,

sendSmsForwardcancel

Messages2: Jack

To : 478-963-7896Text : Hi Jack

sendSmsSaveDelete

Class

Object Tom Object

Jack

Classes and Objects

• Object communicates with each other by sending messages.– Bat Communicates with ball.

Quiz• John is designing a contact management system . Application

should store the details of a person such as ( name, number, email ) . User should be able to add a contact ,update a contact and delete a contact.

Name of the class: Data to be recored. Functionality of contact management system.

Contacts

Name:Numberemail

createContactupdateContactdeleteContact

Contacts1: Tom

Name: TomNumber : 456-789-7895Email :[email protected]


Contacts2: Jack

Name: JackNumber 789-896-8965Email: [email protected]


Quiz

Identify the possible states of a computerHint: A) Sleep

Identify the possible state of a media player

QuestionJohn, is developing a Calculator application. The application should accept two numbers from the user and perform addition, subtraction, multiplication and division on the numbers entered by the user. Help John to design the problem.

Advantages Of Object Oriented Approach

• Realistic Modelling

Advantages Of Object Oriented Programing

• Realistic ModellingBike

String color; String model;Integer speed;

Accelerate()Decelerate()Break()

Advantages Of Object Oriented Approach

• Code Reusability

Contacts1: Tom

Name: TomNumber : 456-789-7895Email :[email protected]


Features Of Object Oriented Programing

• Flexibility to change:

WordAppV1

WordAppV2

NEW

Features Of Object Oriented

• Modularity

Features• Information Hiding– The basic idea is that if code chunk A doesn't

really need to know something about how code chunk B (which it calls) does its job, don't make it know it. Then, when that part of B changes, you don't have to go back and change A

Introduction to JAVA

Software

Transcript of Introduction to JAVA