java class

Class:

                      A class is a blueprint / template it has state and behavior. A class is a logical entity. The collection of objects is also known as class.
State: states means properties of class.
Behavior: Behavior means functionalities of a class.

A java class contains:

·         Methods
·         Data member
·         Constructor
·         Methods
·         Class and interface
·         Objects

Syntax:

                Class <classname> {
                                Data meber;
                                Methods;
                                }

Example: Dog, Bus, Employee

Sample Program:
               
class Employee{
                int id=1;                                                  //data member
                String empname="Smiley";         //data member
               
                void display(){                                   //method
                System.out.println(" Id is "+id);
                System.out.println("emp name"+empname);
                }
               
public static void main(String args[]){
Employee e = new Employee();                                //object of employee class
e.display();
}
}



Types of classes in java:
                There are two types of classes.
   1.       Inner classes
   2.       Outer classes

Inner classes are again 4 types,

1.       Method Local Inner Classes
2.       Static Nested Classes
3.       Member Inner Class
4.       Anonymous Inner Classes

Method Local Inner Classes:
Local inner classes are also known as Method local inner classes. Local inner classes are  accessed inside of the block in which they are defined.

Static Nested Classes:
             A class which is declared with static keyword is known as Static Nested Class. Static classes can be accessed by outer class without an object. We can't create an object for inner classes.

 Member Inner Class:
The Method-Local Inner Classes have access to the specific instance of the enclosing classes
.
Anonymous Inner Classes:
             A class without name is known Anonymous Inner Classes and it doesn’t have constructor.


                                                                             More about Wrapper class


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