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Java Notes ☕

Overview

Java is a popular programming language used to develop mobile apps, web apps, desktop apps, games and much more.

Java is an Object Orient Program (OOP)

Variables/attributes

attribute(vars of type private) = atomic!!!!

Operations/Functions

Getter and setter : way to access and modify an attribute

  • setBalance(): WRITE
  • getBalance(): READ

Class and Object

Class is a blueprint or template from which objects are created

  • variables/attributes + Operations/Functions

Object is an instance of a class at runtime.

class: Student{}

Student myStudent = new Student(); // instantiation

super vs this

  • super: method to access parent method
  • this : current (daughter?) class method

OOP Concepts

Abstraction

process of displaying only required information to the user by hiding other details

Encapsulation

  • private
  • audience
  • protected(visible to inheritors)

Inheritange

An object a (parent) can take b

Polymorphism (static & dynamic) => Java Revolution !!!

Evolution and reuse of the object during its development

Hello World !

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!"); 
    }
}

References

Wikipedia : - https://en.wikipedia.org/wiki/Java_(programming_language)

Wikibooks - https://en.wikibooks.org/wiki/Java_Programming

W3schools Tutorial : - https://www.w3schools.com/java/default.asp

Tools & Frameworks

  • https://www.oracle.com/java/