public interface Duck(){ public void quack(); public void fly(); } public class MallardDuck implements Duck{ public void quack(){ System.out.println("Quack"); } public void fly(){ System.out.println("I'm flying"); } } public interface Turkey{ public void gobble(); //칠면조는 꽥꽥거리지 않습니다. 골골거리는 소리를 내죠. public void fly(); } public class WildTurkey implements Turkey{ public void gobble(){ System.out.pri..