Java / OOP / Abstract - https://www.minte9.com/java/oop-introduction-abstract-1185

abstract.java

/**
 * Define abstact class Animal
 * Class Animal contains two methods, eat() and showName()
 * One of the method is abstract
 */
class App {
    public static void main(String[] args) {
        Dog d = new Dog();
        d.setName("MyDog");
        System.out.println(d.name); // MyDog
    }
}
class Dog extends Animal {
    @Override
    public void eat() {}
}

/**
 * SOLUTION
 */
abstract class Animal {

    public String name;

    public abstract void eat();
    public void setName(String n) {
        name = n;
    };
}