- An abstract class can provide some functionality and leave the rest for derived class.
- The derived class may or may not override the concrete functions defined in base class.
- The child class extended from an abstract class should logically be related.
- An interface cannot contain any functionality. It only contains definitions of the methods.
- We can have a class extend from more than one Interface.
- The derived class must provide code for all the methods defined in the interface.
- Completely different and non-related classes can be logically grouped together using an interface.