Abstract Class vs Interface Table

Feature	Interface	Abstract Class
Multiple inheritance	A class may inherit severalinterfaces	A class may inherit only one abstract class
Default implementation	An interface cannot provide any code, just the signature.	An abstract class can provide complete, default code and/or just the details that have to be overridden.
Constants	Only Static final constants	Both instance and static constants are possible
Speed	Requires more time to find the actual method in the corresponding classes.	Fast
Adding functionality	If we add a new method to an Interface then we have to track down all the implementations of the interface and define implementation for the new method	If we add a new method to an abstract class then we have the option of providing default implementation and therefore all the existing code might work properly.
Homogeneity	If the various implementations only share method signatures then it is better to use Interface	If the various implementations abstract class then we have the common behavior or status then abstract class is better to use.