How to create an object of an abstract class and interface

Question

How do I create an object of an abstract class and interface? I know we can\'t instantiate an object of an abstract class directly.

Answer 1

"instantiate" means "create an object of".

So you can't create one directly.

The purpose of interfaces and abstract classes is to describe the behaviour of some concrete class that implements the interface or extends the abstract class.

A class that implements an interface can be used by other code that only knows about the interface, which helps you to separate responsibilities, and be clear about what you want from the object. (The calling code will only know that the object can do anything specified in the interface; it will not know about any other methods it has.)

If you are using someone else's code that expects a Fooable (where that is the name of some interface), you are not really being asked for an object of some Fooable class (because there isn't really such a class). You are only being asked for an instance of some class that implements Fooable, i.e. which declares that it can do all the things in that interface. In short, something that "can be Foo'd".