Difference between abstract and interface

Question

Accepted Answer

Abstract class is a class that cannot be instantiated and can have both abstract and non-abstract methods. Interface is a blueprint for a class and can only have abstract methods.

Abstract class can have constructors while interface cannot
A class can implement multiple interfaces but can only inherit from one abstract class
Abstract class can have instance variables while interface cannot
Abstract class is used for code reusability while interface is used for achieving abstraction and loose coupling
Example of abstract class: Animal class with abstract method 'makeSound'
Example of interface: Comparable interface with abstract method 'compareTo'

Difference between abstract and interface

Popular interview questions of Automation Test Engineer