Constructor in an Interface? Ask 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 fields in a class are defined for every implementation of this interface.

For example, consider the following class:

public class MyMessage {

   private String receiver;

   public MyMessage(String receiver) {
       this.receiver = receiver;
   }

   public void send() {
       // some implementation for sending the message to the receiver
   }
}