What is Java

Java is high level, class based and object oriented Programming language founded by James Gosling at Sun Micro-systems in 1995 as Java 1.0.
Why Java is More Popular:
James Gosling, Creator of Java
  • Java is a open source programming language created by Sun Microsystems.
  • Java is platform independent language means you can run Java Program on any
    platform(OS + Processor).
  • Java is fast because of JIT compiler.
  • Java provide Garbage collector so it take care of memory.
  • Java is robust and Secure.
  • It is interpreted, Multithreaded and Dynamic.
Versions of Java
  • JDK 1.0 January 23, 1996)
  • JDK 1.1 (February 19, 1997)
  • J2SE 1.2 (December 8, 1998)
  • J2SE 1.3 (May 8, 2000)
  • J2SE 1.4 (February 6, 2002)
  • J2SE 5.0 (September 30, 2004)
  • Java SE 6 (December 11, 2006)
  • Java SE 7 (July 28, 2011)
  • Java SE 8 (March 18, 2014) Source: Wikipedia

Note:

javac

  • When you compile a java program java compiler,it will convert java source file into byte code and extension of byte code is .class.
  • A .class file is JRE dependent but independent of Platform(OS + Hardware). Because a separate JRE is developed for each OS.
What is JIT compiler ?
  •  JIT means just in time Compiler.
  •  Just in time compilation is compilation done during execution of a program
    at run time rather than prior to execution.
  •  It is also known as Dynamic Translation.
  •  JIT is a program that turns java byte code into instruction that can be sent
    directly to the processor.

Parts of Java Language:

As per Sun micro system java is divided into three types:

  1. J2SE/JSE  (java 2 standard edition)
  2. J2EE/JEE (java 2 enterprise edition)
  3. J2ME/JME (java 2 micro edition)

J2SE :- It is  basically used to develop standalone applications.

Eg:- Notepad, Paint, Media Player.

Standalone Applications :-

  • It is installed on a system and run without any client server architecture.
  • It is also called as desktop application or window application.

J2EE :- It is used to develop web based applications like gmail, Facebook, any kind of other websites and tool which runs on the internet.

Web-Applications : 

  • Web-Application runs on internet.
  • Hence they need to have a client server architecture.
  •  It can be launched by using HTTP request/response.

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