JAVA 27 | Abstraction in java | Abstract class in java смотреть онлайн

Abstraction is a process of hiding the implementation details and showing only functionality to the user.
It shows only essential things to the user and hides the internal details, for example, sending SMS where you type the text and send the message. You don't know the internal processing about the message delivery.
Abstraction lets you focus on what the object does instead of how it does it.

ways of achieving abstraction
There are two ways to achieve abstraction in java
Abstract class (0 to 100%)
Interface (100%)
Abstract class in java
A class which is declared as abstract is known as an abstract class.
It can have abstract and non-abstract methods.
It needs to be extended and its method implemented.
an instance of an abstract class cannot be created,but we can have references of abstract class type.
It can have constructors and static methods also.
syntax : abstract class A{ }  
Abstract Method
A method which is declared as abstract and does not have implementation is known as an abstract method.
Example of abstract method
abstract void printStatus( ) ; no  method  body and abstract  

Example of Abstract class
In this example, Bike is an abstract class that contains only one abstract method run. Its implementation is provided by the Honda class.
abstract class Bike{  
  abstract void run( );  
}  
class Honda extends Bike{  
void run(){System.out.println(“in honda class ");}  
public static void main(String args[ ]){  
 Bike obj = new Honda( );  
 obj.run( );  
}  
}
Output :- in honda class