Features Interfaces abstract class
| Multiple inheritance | A class may inherit several interfaces. | 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. |
| Access Modfiers | An interface cannot have access modifiers for the subs, functions, properties etc everything is assumed as public | An abstract class can contain access modifiers for the subs, functions, properties |
| Core VS Peripheral | Interfaces are used to define the peripheral abilities of a class. In other words both Human and Vehicle can inherit from a IMovable interface. | An abstract class defines the core identity of a class and there it is used for objects of the same type. |
| Homogeneity | If various implementations only share method signatures then it is better to use Interfaces. | If various implementations are of the same kind and use common behaviour or status then abstract class is better to use. |
| Speed | Requires more time to find the actual method in the corresponding classes. | Fast |