Why we use Interface?

Question

hai
Can i have a explanation for using Interface (apart from overcoming multiple Inheritance)

Answer 1

**ACK. Got method names mixed up. Though it doesn't really matter, here is the correct mapping from the original reply, to avoid confusion.** :)
This is wrong. You can't have an instance of an interface as you have declared here by saying Draggable drag. Interfaces cannot be instantiated. I think what you meant to say is this:
//understand this is blatantly skeletal
class ConcreteDraggable implements Draggable {
     //these methods must be defined, even if the definition is merely {}
     dragTo(...) {...}
     calcDistance(...) {...}
}And then in the script that uses ConcreteDraggable:
ConcreteDraggable dragThis = new ConcreteDraggable();
dragThis.dragTo(...);
dragThis.calcDistance(...);