Class and Object

What is Object ?

  • An entity which have state and behavior is known as object.
    state defines characteristic of object and behavior defines
    functionality of object
  •  An object is a copy of class each time we create an object
    a copy of class will be created
  •  In the World of java each and everything is Object.


Define class in terms of java ?

  • Class is a definition block which define state and behavior of object
  •  Non static data member defines the state ob object.
  • Non static function member define behavior of object.
Example How to create Object

Let's consider Notebook as object and understand the state and behavior 
of Notebook.

class Notebook

	//characteristic of notebook
	String brand;
	int pages;
	double price;
	//functionality of notebook
	void open()
		System.out.println("open the book");
	void read()
		System.out.println("reading book");	
	void close()
		System.out.println("closing book");
	//method to get details of notebook
	void bookdetail()
		System.out.println("brand name: "+brand);
		System.out.println("number of pages: "+pages);
		System.out.println("price of notebook: "+price);

public class ObjectExample {

	public static void main(String[] args)
        //creating instance of notebbok
		Notebook mbook=new Notebook();
		mbook.brand="class mate";
		mbook.bookdetail();//calling function to get notebook detail
		// creating second instance of notebook
		Notebook mbook1=new Notebook();
	  mbook1.bookdetail();//calling function to get notebook detail



brand name: camel
number of pages: 230
price of notebook: 20.0

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