Introduction to Java (Cheat Sheet)

Last Updated on February 15, 2021 by AbdurRahman G Official | Md Ghufran Salafi

Introduction to Java


What is Java?

Java is an Object Oriented Programming Language Developed by Sun Microsystems of USA in 1991.

It was originally Called “Oak” by James Gosling (One of The Inventors of Java!).


Java = Purely Object Oriented.


How Java Works?

Java is compiled into the bytecode and then it is interpreted to machine code.


|Source Code| -> Compiled -> |Byte Code| -> Interpreted -> |Machine Code|


Java Installation:

Go to Google & Type “Install Java JDK” => Download and Install it.

Go to Google & Type “Install (IDE Name) Like: IntelliJ Idea => Download and Install it.


JDK = Java Development Kit = Collection of Tools used for developing and running Java Programs.

JRE = Java Runtime Environment = It helps in executing programs developed in Java.


Basic Structure of a Java Program:

package; -> Group of Classes

public class Main {

public static void main (String[] args) {

System.out.println(“Hey, World!);










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