why i could not create new dog class and object like as cat class ?

Question

interface Animal {
public void eat();
public void makeSound();
}

class Cat implements Animal {
public void makeSound() {
System.out.println("Meow");
}
public void eat() {
System.out.println("omnomnom");
}
}

class Dog implements Animal {
public void makeSound() {
System.out.println("brow");
}
}

public class Program {
public static void main(String[] args) {
Cat c = new Cat();
c.eat();
Dog d = new Dog();
d.makeSound();
}
}

/* output is ;
..\Playground\:4: error: Dog is not abstract and does not override abstract method eat() in Animal
class Dog implements Animal {
^
1 error */

Answer 1

When you implement an interface, you have to override all of its methods (eat is missing). As long, as you don't create an abstract class.