Class in JAVA

BASIC
All the objects that have similar properties and similar behavior are grouped together to form a class. Class is the java way to implement encapsulation.A class is a user defined data type and objects are the instance variables of class.



GENERAL FORM OF CLASS

A class is declared by use of the class keyword.The data, or variables, defined within a class are called instance variables because each instance
of the class (that is, each object of the class) contains its own copy of these variables.

class class name {

type instance variable;

//

type method name(parameter-list) {

//body of method

}

to access the instance variables and methods declared within a class and assign values to instance variable we need to create object of class using dot (.) operator.

object of class is created as classname obj =new classname();

class area(){

double length;

double width;

}

class calculatearea()

{

public static void main(String args[])

{

area obj=new area();

double area;

obj.length=9;

obj.breath=4;

area=obj.length*obj.breath;

System.out.printllln(“area is”+area);

}

}

concept of object

object of a class is created by new operator.

The new operator dynamically allocates (that is, allocates at run time) memory for an object and returns a reference to it. This

reference is, more or less, the address in memory of the object allocated by new.This reference is then stored in the variable.