Core Java - SPLessons
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Java Tutorial

Core Java - SPLessons

Java Tutorial

shape Introduction

SPlesson Java Tutorial will guide and explains each and every concept in Java, to learn Java user do not need to have knowledge of other languages, without knowing other languages it is simple to learn without any confusion.

What is Java?

shape Description

Initially Java is called as OAK, in the 1995 it is renamed as Java, as part of Java some modules are there like Core Java is utilized to develop stand alone applications and it will be in the form of two tier architecture. Advanced Java is utilized to develop the web applications by using Servlets, JSP and it will be in the form of three tier architecture. The Java enterprise edition is utilized to develop distributed applications and it will be in the form of the entire architecture. As part of Java JME (Java mobile edition) is utilized to develop mobile applications.

History of Java

shape Description

The small team of engineers, known as Green Team( James Gosling, Mike Sheridan and Patrick Naughton), initiated the language in 1991. Java was originally called OAK, and was designed for handheld devices and set-top boxes. Oak was unsuccessful.So in 1995, Sun changed the name to Java.Later in 2009, Oracle Corporation acquired Sun Microsystems and took ownership of two key Sun software assets Java and Solaris.

shape Basic Code

Class Splessons{
public static void main(String args[]){
System.out.println("Stop thinking Start coding");
}
}

In the above example, Splessons is the name of the class and void is the return type and println is used to print the statement.
Output: Now compile the code result will be as follows.

Stop thinking Start coding

What is System.out.println()

  • out is an object PrintStream class defined in System class. out is declared as public, static and final.
  • The println() is a method of PrintStream class.
  • The println() method is called with out object.
  • The out object is called with System class.
  • Java Versions

    shape Table

    The following are the versions of the Java.

    Name Date
    JDK Alpha and Beta 1995
    JDK 1.0 23rd Jan 1996
    JDK 1.1 19th Feb 1997
    J2SE 1.2 8th Dec 1998
    J2SE 1.3 8th May 2000
    J2SE 1.4 6th Feb 2002
    J2SE 5.0 30th Sep 2004
    Java SE 6 11th Dec 2006
    Java SE 7 28th July 2011
    Java SE 8 18th March 2014

    Features of Java 8


    Java Releases

    shape Editions

    1. Java Standard Edition: It is the Standard Edition for the Core Java application.
    Eg: Calculator.
    2. Java Enterprise Edition: It is the Enterprise Edition for the Enterprise application/Web application.
    Eg: Gmail
    3. Java Micro Edition:It is Micro Edition for Mobile application.
    Eg: Android 

    Java Components

    shape Description

    Main 2 java components are Compiler and Interpreter.These are also called as Translators.

    Compiler is a computer program that transforms source code written in programming language into another computer language(target language often having binary form called object code).

    Translates high level language—>low level language.

    An Interpreter translates high level instructions into an intermediate form,which it then executes.(It interprets code line by line).

    Difference between interpreter and compiler.

    Interpreter:

  • Interpreter translates program one statement at a time.
  • Interpreter takes less amount of time to analyze the source code but the overall execution time is slower.
  • Programming language like Python, Ruby use interpreters.
  • Compiler:

  • Compiler scans the entire program and translates it as a whole into machine code.
  • Compiler takes large amount of time to analyze the source code but the overall execution time is comparatively faster.
  • Programming language like C , C++ use compilers.
  • Summary

    shape Key Points

  • Java Tutorial – Java is just a name, it does not have any acronym.
  • Java Tutorial – JVM stands for Java virtual machine to compile the code successfully.
  • Java Tutorial – Java class file will have byte code instructions.