Java is an object-oriented programming language and platform. It was developed at Sun Microsystems in 1995 to be portable and high-performance. Java applications can run on many systems without recompilation because it uses a virtual machine that translates bytecode into native machine code. The key components of Java are the JVM (Java Virtual Machine), JRE (Java Runtime Environment), and JDK (Java Development Kit). The JVM executes Java bytecode, while the JRE provides libraries and tools for developing Java applications. The JDK is a superset of the JRE and includes development tools like compilers and debuggers.

2. What is java?
Java is a programming language and a platform.
"Write once, run anywhere" (WORA), or sometimes “write once, run everywhere”
(WORE), is a slogan created by Sun Microsystems to illustrate the cross-platform
benefits of the Java language.
This language was developed at SUN Microsystems in the year 1995 under the
guidance of James Gosling and team.
Platform: Any hardware or software environment in which a program runs, is
known as a platform. Since Java has its own runtime environment (JRE) and API, it
is called platform.

3. Features of Java
1- Simple
2- Object-Oriented
3- Platform independent
4- Secured
5- Robust
6- Architecture neutral
7- Portable
8- Dynamic
9- Interpreted
10- High Performance
11- Multithreaded
12- Distributed

4. Software & tools required
Software & Tools-
1- Linux 7.1 or Windows xp/7/8 operating system
2- Java JDK 8
3- Microsoft Notepad or any other text editor
4- Eclipse or NetBeans .

5. JVM , JDK & JRE

6. JVM
● JVM (Java Virtual Machine) is a software.
● It is a specification that provides runtime environment in which java bytecode
can be executed.
● It not physically exists.
● JVMs are not same for all hardware and software,for example for window os
JVM is different and for Linux JVM is different.
● JVM, JRE and JDK are platform dependent because configuration of each OS
differs. But, Java is platform independent.

7. JRE
● The Java Runtime Environment (JRE) is part of the
Java Development Kit (JDK).
● It contains set of libraries and tools for developing
java application.
● The Java Runtime Environment provides the
minimum requirements for executing a Java
application.
● It physically exists.
● It contains set of libraries + other files that JVM
uses at runtime.

8. JDK
● The Java Development Kit (JDK) is
primary components.
● It physically exists.
● It is collection of programming tools
and JRE, JVM.

9. Copy this path and set it as PATH in user
variables
Setting Up of Environment

10. Environment Setup
1- goto- Control Panel>System
and Security>System.
2- click on Advance System
Settings tab on left sidebar.
3- It will open System Properties
tab and click on Advanced tab.
4- Bottom|Right has
Environment Variable Button,
click on it.
5- Set PATH in User variables
and Set JAVA_HOME in System
variables .
1st
2nd

11. Where JAVA is used?
● Desktop Applications such as acrobat reader, media player, antivirus etc.
● Web Applications such as irctc.co.in, javatpoint.com etc.
● Enterprise Applications such as banking applications.
● Mobile
● Embedded System
● Smart Card
● Robotics
● Games etc.

12. Types of JAVA Application
There are mainly 4 type of applications that can be created using java
programming:
1- Standalone Application- Antivirus, Media Player etc.
2- Web Application- JSP, Servlets etc. used to make web application
3- Enterprise Application- JAVA EE at business tier
4- Mobile Application. Android and JAVA ME.

13. First Program “Hello World”
1- open text editor and write first program
2- Save it as Hello.java
3- Open command prompt or terminal .
4- Go to the file and to compile code write
“javac Hello.java” command.
5- to run “java Hello”.
class Hello {
public static void main (String args[])
{
System.out.println("Hello JAVA");
}
}

14. Compile and Execute

15. Class in JAVA
“class is the only logical entity.”
Class: Class is a blueprint which is containing only list of variables and method
and no memory is allocated for them. A class is a group of objects that has
common properties.
A class in java contains:
1- Data Member, 2- Method, 3- Constructor
4- Block, 5- Class and 6- Interface

16. Object in JAVA
“Object is the physical as well as logical entity.”
Object: Object is an instance of class, object has state and behaviors.
An Object in java has three characteristics:
1- State 2- Behavior 3- Identity
State: Represents data (value) of an object.
Behavior: Represents the behavior (functionality) of an object
Identity: Object identity is typically implemented via a unique ID.

17. Real Life example of Object and class.
Class: vehicle
Object: car, bus, bike, truck are
object of vehicle class.
State: Color, Model,speed
Behaviour: Travelling
Identity: unique number

18. “Variable is a name of memory location or name of reserved area allocated in
memory.”
There are three types of variables in java
1- local variable ` 2- instance variable 3- static variable
A variable that is declared inside the
method is called local variable.
A variable that is declared inside the class
but outside the method is called instance
variable . It is not declared as static.
A variable that is declared as static is
called static variable. It cannot be local.
Variables and Datatypes in JAVA

19. DATA Types
Basically two types of
data type :
Primitive
&
Non-Primitive