How To Use Java Class or Object With Examples
How To Use Java Class or Object With Examples 


How To Use Java Class or Object With Examples 

Class: A Java object Oriented Programming Language tries to map code instructions with real words making the code short and easier to understand.

Class: A class is a blueprint from which objects are created. an object is the instance of a class. class is a collection of data members and member functions.

Data members are the variable used inside the class. Member functions are the function used inside the class. It is also called a User-defined data type.

What is an object-oriented Programming Language.?

Object: A object is an instruction of the class. when a class is defined as a template. Memory is allocated only after object instructions.

Java is an Object-oriented Programming Language is solving a problem by creating an object is one of the popular approaches is called the object-oriented Programming Language.

What is the Dry Concept?

Dry: A Dry Concept is called the Do Not Repeat Yourself.

Same Other Topic Post Learn.

👉Pointer 


👉Function


👉String


👉Array 

👉Structure

👉Union


How To Model Problem Object-Oriented Programming?


Class: Student

Attribute:id,name,age,Mark's,

Method:get.id(),getname()

Object: A object is having states and behaviors in which state means what does it has and behavior means what does it do.


Syntax of class

class class name

{

Access specifier Data member 1;

Data member 2;

Member function 1;

Member function 2;

}


How To Create Java Class

class Rectangle 


//Data Member 

int h; 

int w; 

int area; 

//Member function 

void findArea() 


area=h*w; 

System.out.println("Area of Rectangle:"+area); 


public static void main(String[] args) 


//creating object 

Rectangle ob=new Rectangle(); 

//accessing data member 

ob.h=10; 

ob.w=15; 

//accessing member function 

ob.findArea(); 



*****Output***** 

Area of Rectangle:150


Access Modifiers in java 

An Access Specifier where property and method are accessible.

Access Modifiers are Four Types.

1. Public 

2. Private

3. Protected

4. Default

Contractors in Java: A Java contractor is a special member function of a class that executes.

when we create the object of that class in other words we can say that there is no need to call a constructor. L

Its name is the same as the class name. It has no return type. It may be parameterized or non-parameterized. It is used to initialize the class level variable.


How To Create Constructor in Java?

class Rectangle 

 
int h; 

int w; 

int area;  

Rectangle()//Constructor 


h=10;

w=15;

area=h*w;

System.out.println("Area of Rectangle:"+area); 


public static void main(String[] args) 


Rectangle ob=new Rectangle();    



*****Output***** 

Area of Rectangle:150


Three Types of constructors in Java


1. Default Constructor.

2. Parameterized Constructor.

3. Copy Constructor.



Default Constructor: A Default constructor is a  no parameter is called default constructor.


How To Create Default Constructor in Java?

class Rectangle 

 

int h; 

int w; 

int area;  

Rectangle()// Default Constructor 


h=10;

w=15;

area=h*w;

System.out.println("Area of Rectangle:"+area); 


public static void main(String[] args) 


Rectangle ob=new Rectangle();    



*****Output***** 

Area of Rectangle:150


Parameterized Constructor: A parameters constructor with parameters is called the parameterized constructor.


How To Create Parameter Constructor in Java?

class Rectangle 

 

int area;  

Rectangle(int h,int w)// Parameter Constructor 


area=h*w;

System.out.println("Area of Rectangle:"+area); 


public static void main(String[] args) 


Rectangle ob=new Rectangle(10,15);    



*****Output***** 

Area of Rectangle:150


Copy Constructor: 
A Copy constructor is0 type of constructor one object with a parameter is copied into another object so it is called a copy constructor.


How To Create Copy Constructor in Java?

class Rectangle 

 
int area;  

Rectangle(int h,int w)// Copy Constructor 


area=h*w;

}

void show()

{

System.out.println("Area of Rectangle:"+area); 


public static void main(String[] args) 


Rectangle ob=new Rectangle(10,15);    

ob.show();

Rectangle ob1=ob;

ob1.show();



*****Output***** 

Area of Rectangle:150

Area of Rectangle:150