1. Write once run anywhere
A presentation on core java by :
Roushan Kumar sinha
B.Tech – I.T (4th yr.)

2. Contents
 What is java ?
 Where java used ?
 java platforms / Editions
 Feature of java.
 Java virtual machine.
 Java Architecture.
 Why java is platform independent ?
 What is oop ?
 Concept of oop.
 Data types in java.

3. What is java ?
 Java is a high level object oriented programming language as well
as platform.
 Java was developed by a team led by James Gosling at Sun
Microsystems and released in 1995.
 Java runs on a variety of platforms such as Windows, mac os ,
and the various version of UNIX.

4. Where java used ?
According to sun , 3 billion devices run java. There are many
Devices where java is currently used. Some of them are as follows:
 Desktop applications such as acrobat reader , media player ,
antivirus ,etc.
 Web Applications such as Irctc , javatpoint.com , linkedin ,etc.
 Enterprise applications such as banking applications.
 Mobile
 Embedded system
 Smart card
 Robotics
 Games ,etc

5. Java platforms / Editions
Java
Java SE (java standard edition)Java EE(java Enterprise edition)
Java ME (java micro Edition) javaFx

6. Features of java
Object oriented
Simple
Platform independent
Robust
Architectural neutral
Portable
Secured
Interpreted
Multithreaded
Dynamic

7. JVM
 JVM (java virtual machine) is an abstract machine . It is a specification that
provides runtime environment in which Java bytecode can be executed.
 JVMs are available for many hardware and software platforms . (i.e. JVM is
platform dependent)
 JVM performs following operation:
 Loads code
 Verifies code
 Execute cod
 Provides run time environment

8. Java Architecture

9. Java example
Class Simple
{
public static void main (String arg[])
{
System.out.println(“Hello Java”);
}
}
// To compile this code in cmd :
Javac <filename>.java
//To run this code :
Java <classname>

10. Why java is platform independent ?

11. What is oop ?
 Object oriented programming is a method of implementation.
 A language in which everything is represented in the form of object is
called object oriented programming language.
 Java follow the oop’s concept but not 100 percent.
 Simula is considered as the first object – oriented programming
language.
 The popular object oriented languages are java , c# , Python ,c++,etc.

12. Oop’s concept
• Object
• Class
• Inheritance
• Polymorphism
• Abstraction
• Encapsulation

13. Data types in java

14. Java variables
1. Local variable : A variable declare
inside the body of method is called
local variable.
2. Instance variable : A variable declare
inside the class but outside the body
of the method but it is not declared as
static.
3. Static variable :A variable which is
declared as static is called static
variable . It cannot be local .
single entity can be shared among
multiple objects. Static variable
allocated only one time in memory when
class is loaded.

15. Advantages of java
 Java is simple language.
 Java does not support POINTERS.
 Java is the first language in which program can be executed using web.
 Write once run anywhere.