what's the exact differences between interface and abstract class ?

Answer 1

Interfaces have complete abstract methods. Attributes within interfaces are both final and static by default. Intefaces must be implement in order to provide functionality to those behaviours.

Abstract classes may have abstract methods and non abstract methods. Abstract classes cannot be instantiated and one must inherit the abstract class in order to provide functionality to those abstract behaviours.

Answer 2

yaa but abstract class can be extended in another class

Answer 3

Which i did mention above. "Inherit".

Answer 4

yaa i didn't see that 👍