The JAVA Language

1. Object Oriented Technology The JAVA Language Mithani Binjan M

2. Programming Languages • To adapt to • changing environments and uses • To implement • refinements and improvements • in the art of programming

3. History of OOPs • In 1960s Birth of Structured Programming Language • In early 1980s object-oriented programming (OOP)

4. History of OOPs • In 1979 C++ invented by Bjarne Stroustrup • 1980s and the early 1990s, C++ took hold.

5. 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)

6. 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

7. 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.

8. Java’sMagic: 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

9. JVM • Interpreter • JVM needs to be implemented for each platform. • Platform independent • Bytecode enables the Java run-time system to execute programs much faster

10. 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.

11. Java Buzzwords • Multithreaded • Architecture-neutral • Interpreted • High performance • Distributed • Dynamic • Simple • Secure • Portable • Object-oriented • Robust

12. Java Versions • Java 2, version 1.4 • Java 2, version 1.5 • Java 2, version 1.6 • Java 1.0 • Java 1.1 • Java 2 • Java 2, version 1.2 • Java 2, version 1.3

13. Java the OOP Language • The Three OOP Principles • Encapsulation • Inheritance • Polymorphism • Abstraction

14. Encapsulation A B getA() getB( )

15. Inheritance Bird Flying Non-Flying Robin Swallow Penguin Kiwi

16. Polymorphism Shape Draw( ) Draw( a, b ) Draw( a ) Draw( a, b, c ) Triangle Circle Rectangle

17. Object Object : Student • Run time entity • Represent a PERSON, BOOK, • Bank Account, etc… • User defined data • Example: DATA: Roll_no Name Percentage FUNCTIONS: Total Average Display

18. Class CLASS • Set of Data & Code is class • User defined data-type • Example: • Fruit, • Furniture • Vehicle DATA: ::::::::::::: ::::::::::::: FUNCTIONS: :::::::::::: ::::::::::::

19. 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

20. Type Size in bytes Description Keyword Character 2 16-bit Unicode char Boolean - true / false 1-bit boolean Byte 1 8-bit byte Short 2 16-bit short Integer 4 32-bit int Long 8 64-bit long Float 4 32-bit float Double 8 64-bit double Data Types • Java supports eight different basic data types.

21. Declaration &Initialization of variable Datatype varName; // Declaration of Variable varName = Value; Example: int count = 22;

22. 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;

23. Declaration &Initialization of variable long m = 254836L; System.out.println(“The value of m is “ + m); Output: The value of m is 254936

24. Declaration &Initialization of variable Character & Strings char ch = ‘A’; String s1= “This is Testing”; //String is a class provide by Java.

25. Guess the Output Class 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); } }