Constructor in an Interface?

Question

I know it\'s not possible to define a constructor in an interface. But I\'m wondering why, because I think it could be very useful.

So you could be sure that some fi

Answer 1

If you want to make sure that every implementation of the interface contains specific field, you simply need to add to your interface the getter for that field:

interface IMyMessage(){
    @NonNull String getReceiver();
}

• it won't break encapsulation
• it will let know to everyone who use your interface that the Receiver object has to be passed to the class in some way (either by constructor or by setter)