INTRODUCING CLASSES:

A class is a blueprint of set of objects that share common characteristics and behaviour. An object is its instance.

A method is an association operation of an object. The 'behaviour' of object is represented through methods.

Objects represent the abstraction represented by the class in real sense.

A class represents an abstraction where characteristics are implemented through data and behaviour through methods or functions.

In OOP(object oriented programming), objects are defined by defining a class for them.

Object Factory is producer of objects, that accepts some basic information and creates objects based on that information.

A class is an Object Factory. It contains all statements needed to create an object, its attributes as well as statements describing operations that the object will be able to perform.

CONCEPTS OF OBJECTS:

OBJECTS:

AN OBJECT CAN BE THOUGHT AS AN ENTITY HAVING SPECIFIC IDENTITY , CHARACTERISTICS AND BEHAVIOUR.

 

STATE OF OBJECTS:

THE STATE OF OBJECT IS REPRESENTED THROUGH ITS VALUES OR ATTRIBUTES OF ITS CHARACTERISTICS AT A GIVEN POINT OF TIME.

 

ABSTRACTION:

ABSTRACTION REFERS TO THE ACT OF REPRESENTING ESSENTIAL FEATURES WITHOUT INCLUDING BACKGROUND DETAILS AND EXPLANATION. IT IS ALWAYS RELATIVE TO CONTENT.

 

ENCAPSULATION:

THE WRAPPING UP OF DATA AND FUNCTIONS INTO SINGLE UNIT(OBJECT) IS CALLED ENSCAPSULATION. IT IS THE WAY TO IMPLEMENT DATA ABSTRACTION. IT HIDES THE DETAILS OF THE IMPLEMENTATION OF OBJECTS.

 

 

SINCE STATE AND BEHAVIOUR OF OBJECT ARE INTERWOVEN, THEY ARE SAID TO ENCAPSULATE STATE AND BEHAVIOUR.WE CANNOT SEGRGATE THEM. THUS, WE CAN SAY OBJECTS ENCAPSULATE STATE AND BEHAVIOUR, AS THEIR STATE  AND BEHAVIOUR ARE INTERLINKED. THUS THEY CANNOT EXIST SEPARATELY.

 

STATE IS MAINTAINED THROUGH VARIABLES OR DATA ITEMS (MEMBER VARIABLES THAT HOLD DATA).BEHAVIOUR IS MAINTAINED THROUGH FUNCTIONS OR METHODS

 

WHEN OBJECTS NEED TO INTERACT WITH ONE ANOTHER, THEY INTERACT BY PASSING MESSAGES TO ONE ANOTHER. THIS IS KNOWN AS MESSAGE PASSING.

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HELLO FRIENDS!
I AM NOW GOING TO HELP YOU GUYS WITH THE THEORY PART OF JAVA ALSO.
MY NOTES WILL DEFINITELY HELP ICSE STUDENTS SCORE MAXIMUM MARKS IN THEIR COMPUTER APPLICATIONS PAPER.

I WILL KEEP UPLOADING MY NOTES ON WEEKLY BASIS.

RIGHT NOW I AM STARTING WITH THE BASIC CHAPTER IN JAVA.