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 


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.


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



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