**Data abstraction** is a method where essential elements are displayed to the user and trivial elements are kept hidden.

In Java, abstraction is achieved by using the `abstract` keyword for classes *and* interfaces. In abstract classes, we can have abstract methods as well as concrete methods.

# Code
The following piece of code shows abstraction in Java:

// Abstraction in Java
abstract class ElectricityBill 
{ 
	//abstract method 
	abstract float computeBill(); 
} 

class Commercial extends ElectricityBill 
{ 
	@Override
	float computeBill() { 
		return 1.25*100; 
	} 
} 

class Domestic extends ElectricityBill 
{ 
	@Override
	float computeBill() { 
		return 0.25*75; 
	} 
} 

How to implement abstraction in Java

Abstraction hides trivial details by using abstract classes and interfaces in Java.