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The
JAVA Language
Object Oriented
Technology
Mithani Binjan M
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Programming Languages
•To adapt to changing environments and uses•To implement
refinements and improvements
in the art of programming
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History of OOPs In 1960s Birth of Structured
Programming Language
In early 1980s object-oriented
programming (OOP)
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History of OOPs In 1979 C++ invented by
Bjarne Stroustrup 1980s and the early 1990s,
C++ took hold.
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History of OOPs In 1991 Java was conceived
By James Gosling, Patrick Naughton, Chris Warth, Ed Frank, and Mike Sheridan
At Sun Microsystems, Inc.
“Oak” “Java” (1995)
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Java the Language of Internet
Expanded the universe of objects Objects can move about freely
in cyberspace. On a network :
passive information/data dynamic, active programs
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Java Applications -&- Java Applets
An application is a program that runs on your computer, under the operating system of that computer. An applet is an application designed to be transmitted over the Internet and executed by a Java-compatible Web browser.
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Java’s Magic: The Bytecode
An application a highly optimized set of instructions designed to be executed by the Java run-time system - JVM JVM - Java Virtual Machine Truly Portable
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JVM Interpreter JVM needs to be implemented for each
platform. Platform independent Bytecode enables the Java run-time system to execute programs much faster
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Just In Time (JIT) compiler
Sun supplies its Just In Time (JIT) compiler for bytecode. (Java-2) JIT compiler is part of the JVM. It compiles bytecode into executable code in real time, on a piece-by-piece, demand basis.
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Java Buzzwords SimpleSecurePortableObject-orientedRobust
MultithreadedArchitecture-neutralInterpretedHigh performanceDistributedDynamic
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Java Versions Java 1.0Java 1.1Java 2Java 2, version 1.2Java 2, version 1.3
Java 2, version 1.4Java 2, version 1.5 Java 2, version 1.6
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Java the OOP Language The Three OOP Principles
• Encapsulation
• Inheritance
• Polymorphism
Abstraction
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Encapsulation
getB( )
A B
getA()
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InheritanceBird
Flying Non-Flying
Robin Swallow Penguin Kiwi
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PolymorphismShape
Draw( )
Draw( a, b ) Draw( a ) Draw( a, b, c )
Rectangle Circle Triangle
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Object• Run time entity
• Represent a PERSON, BOOK,
Bank Account, etc…
• User defined data
• Example:
Object : StudentDATA: Roll_no Name Percentage
FUNCTIONS: Total Average Display
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Class• Set of Data & Code is class
•User defined data-type
• Example: Fruit, Furniture Vehicle
CLASS
DATA: ::::::::::::: :::::::::::::
FUNCTIONS: :::::::::::: ::::::::::::
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Variables & Data Types• Named memory location that holds a value
• In java variables must be declared before it use in the program
• Variable must be of some datatype, it tells
compiler what type of value it can store
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Data Types• Java supports eight different basic data types.
TypeSize in bytes
Description Keyword
Character 2 16-bit Unicode
char
Boolean - true / false 1-bit boolean
Byte 1 8-bit byteShort 2 16-bit shortInteger 4 32-bit int
Long 8 64-bit longFloat 4 32-bit floatDouble 8 64-bit double
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Declaration & Initialization of variable
Datatype varName; // Declaration of Variable
varName = Value;
Example:
int count = 22;
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Declaration & Initialization of variable
float x, y, z;
// value here considers as ‘double’ type
x = 10.35;
x = 10.35f;
y = 24.56F;
z = y;
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Declaration & Initialization of variable
long m = 254836L;
System.out.println(“The value of m is “ + m);
Output:
The value of m is 254936
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Declaration & Initialization of variable
Character & Strings
char ch = ‘A’;
String s1= “This is Testing”;
//String is a class provide by Java.
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Guess the OutputClass test
{
public static void main(String s[])
{
char c;
boolean flg;
int a;
System.out.println(c);
System.out.println(flg);
System.out.println(a);
}
}