Introduction to Java

Java/J2EE Programming Training
Introduction to Java

Classification: Restricted
Agenda
• Java History
• Features of Java
• Java Versions
• Application Area

Features Of Java
• Simple
• Object-Oriented
• Platform independent
• Secured
• Robust
• Architecture neutral
• Portable
• Dynamic
• Interpreted
• High Performance
• Multithreaded
• Distributed

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

RMI

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 Versions
Year Version Platform CodeName Features
1996 1 1.0
1997 1.1 1
1998 1.2 2 Playground Swings, Frameworks
2000 1.3 2 Kestrel Assertion, chained exceptions
2002 1.4 2 Merlin
2004 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 swich
Try-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

JIT ( Just In Time Compiler)

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

• 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.

• Consists of classes and object.
• Object communicates with each other by passing messages
What is an
object????

• Object is an instance of class
• Object is an real time entity
• State
• Behavior
• Identity NotePad Code{
filename
Text:
readOnly
Open()
Close()
Minimize()
Maxmize
Save()
}
Object = Instance Of Notepad

Object States
An 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:
Dog
State:
Name
Breed
Height
Weight
Behaviour:
eat()
run()
walk()

Classes
• Collection of objects
wheelsSeats
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
To
Text
sendSms
Forward
cancel
Messages1: Tom
To : 123-456-7896
Text : Hi Tom,
sendSms
Forward
cancel
Messages2: Jack
To : 478-963-7896
Text : Hi Jack
sendSms
Save
Delete
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:
Number
email
createContact
updateContact
deleteContact
Contacts1: Tom
Name: Tom
Number : 456-789-7895
Email :tom@gmail.com
createContact
updateContact
deleteContact
Contacts2: Jack
Name: Jack
Number 789-896-8965
Email: jack@gmail.com
createContact
updateContact
deleteContact

Quiz
Identify the possible states of a computer
Hint: A) Sleep
Identify the possible state of a media player

Question
John, 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 Modelling
Bike
String color;
String model;
Integer speed;
Accelerate()
Decelerate()
Break()

Advantages Of Object Oriented Approach
•Code Reusability
Contacts1: Tom
Name: Tom
Number : 456-789-
7895
Email
:tom@gmail.com
createContact
updateContact
deleteContact

Features Of Object Oriented Programing
• Flexibility to change:
WordAppV1 WordAppV2

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

Thank You

Introduction to Java

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