What is the difference between an abstract class and interface?

Feature	Interface	Abstract class
Declaration and implementation of Methods	Contain only declaration of functions and methods. It does not provide implementation of methods.	We Can provide default implementation of methods.
Implement Every Method or Override every method	The derived class must implement all the methods of interface.	Not necessary to implement all methods.
Fields and Constants	Fields can not be define	Fields can be define.
Access Modfiers	An interface cannot have access modifiers for the functions, properties etc everything is assumed as public	An abstract class can contain access modifiers for the functions, properties