What is abstraction in programming?

Question

I heard that abstraction is the heart of programming.What is actually abstraction?is it something to do with abstract classes?(Explain with respect to JAVA)

Answer 1

"Abstraction" as a concept means that you hide unnecessary details from a user/programmer.
For example, when you use Math.pow(a, b), then *how* the function works is hidden from you.

An abstract class uses a similar concept. You create an abstract class which will just lay the groundwork for its derived classes, i.e. each derived class of an abstract class will have its own different methods and properties.
An abstract class carries no details in itself. The *details* are present in its derived classes.