Object-Orirnted Programming Language


Introduction

OOPS stand for object oriented system, it is a standered or guidline which tells us how to develop robust scalable & secure software system

Importent Points

  • There are 2000 software companies having OMG like Oeacle, Microsoft, Google, etc

  • OOPS is not a language, it is a standered manage by OMG ( object management group )

  • OOPS is a methodology or paradigm to design a program using classes and object it simplyfies the software development and maintenance by providing some concept



Object-
  • What are objects ? They are software programming models. In your everyday life, you are surrounded by objects: cars, coffee machines, ducks, trees, and so on. Software applications contain objects: buttons on user interfaces, spreadsheets and spreadsheet cells, property lists, menus, and so on. These objects have state and behavior. You can represent all these things with software constructs called objects, which can also be defined by their state and their behavior.
  • Any intity that has behaviour and state is known as a object ( Such as Chair , Pen , Keyboard ,Bike )
  • It can be physical and logical.
Class-

    Collection of objects is known as classs . it is a logical intity

    State is Noun & Behaviour is Verb

Data Types-

    Data Types are Divided in 4 Types



Java Variables-

    Instance variable
    • Those variable which are discribe inside the class and whose one copy is given to thier instances or objects.
    • An instance is free to operate their own copy of variable


    Class variable
      Static Variable:- Classes not allowed to share its own copy with Instances.

      Class Variables are those variable which are declair inside of the class with static keyword are called as class variable
      • static variable initialized at once at memory & only one copy created in memory
      • all the instances or the object can now share the copy of class variable




    Local variable
      variables which are defines inside of the mathod , constructors,or blocks are called as locla variable . The variable will be declaired and initialised wihin the mathod and the variable will be distroyed when the method is completed