Introduction to java
Java is a programming language it was developed by Sun Microsystems in 1991, later acquired by Oracle Corporation. It was developed by James Gosling, Bill Joy, Mike Sheradin, Patrick Naughton. 

Java software development was initiated in 1991 and released in 1995. It is known as a high-level language because it can be read and written easily by users. 

Java is a fast, simple, reliable, secured and object-oriented programming language. Java runs on a different platforms, such as Windows, UNIX/LINUX, Mac OS.

Java program can run on a wide variety of computers because it does not execute instructions on a computer directly. Instead, Java runs on a Java Virtual Machine (JVM).

Vendor Sun Micro System
Project name Green Project
Type open source & free software
Initial Name OAK language
Present Name java
Extensions .java & .class & .jar
Initial version jdk 1.0 (java development kit)
Present version java 8 2016
Operating System multi Operating System
Implementation Lang c, cpp;
Symbol coffee cup with saucer
Objective To develop web applications
SUN Stanford Universally Network
Slogan/Motto WORA(write once run anywhere)
Java Sample program
Class Test 
{ 
Public static void main (String [] args) 
 { 
System.out.println ("welcome to java language"); 
   } 
}​
Output :
Compilation :- javac FileName.java

Execution :- java Class Name

Output :- welcome to java language
Importance of core java
According to the SUN 3 billion devices run on the java language only.

1) Java is used to develop Desktop Applications such as
 MediaPlayer,Antivirus etc.
 2) Java is Used to Develop Web Applications such as freetimelearning.com, irctc.co.in, onlinesbi.com etc.
 3) Java is Used to Develop Enterprise Application such as Banking applications.
4) Java is Used to Develop Mobile Applications. 
5) Java is Used to Develop Embedded System.
6) Java is Used to Develop SmartCards. 
7) Java is Used to Develop Robotics.
 8) Java is used to Develop Games etc.
Java Vertions :
Version Year
JavaAlpha & beta 1995
JDK 1.0 1996
JDK1.1 1997
J2SE 1.2 1998
J2SE 1.3 2000
J2SE 1.4 2002
J2SE 1.5 2004
JAVA SE6 2006
JAVA SE7 2011
JAVASE8 2016