Polymorphic mapping with jackson

Zoo.java

import java.util.ArrayList;
import java.util.List;

import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;

public class Zoo {

    @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
    @JsonSubTypes({ @JsonSubTypes.Type(value = Dog.class, name = "dog"), @JsonSubTypes.Type(value = Cat.class, name = "cat"), })
    public static abstract class Animal {
        public Animal() {
        }

        public Animal(String name) {
            this.name = name;
        }

        public String getName() {
            return this.name;
        }

        public void setName(String s) {
            this.name = s;
        }

        public Animal getParent() {
            return this.parent;
        }

        public void setParent(Animal p) {
            this.parent = p;
        }

        private String name;
        private Animal parent;
    }

    @JsonTypeName("dog")
    public static class Dog extends Animal {
        public Dog() {
        }

        public Dog(String name) {
            super(name);
        }
    }

    @JsonTypeName("cat")
    public static class Cat extends Animal {
        public Cat() {
        }

        public Cat(String name) {
            super(name);
        }
    }

    public static void main(String... args) throws Exception {
        Zoo zoo = createZoo();

        ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
        String json1 = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(zoo);
        System.out.println("+++>>>" + json1);

        zoo = mapper.readValue(json1, Zoo.class);

        String json2 = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(zoo);

        System.out.println("Equals: " + json1.equals(json2));
    }

    private static Zoo createZoo() {
        Zoo zoo = new Zoo();

        Dog dog1 = new Dog("Dog1");
        Dog dog2 = new Dog("Dog2");
        Cat cat1 = new Cat("Cat1");
        Cat cat2 = new Cat("Cat2");

        dog2.setParent(dog1);
        cat2.setParent(cat1);

        zoo.add(dog1);
        zoo.add(dog2);
        zoo.add(cat1);
        zoo.add(cat2);

        return zoo;
    }

    private List<Animal> animals = new ArrayList<>();

    public void add(Animal animal) {
        animals.add(animal);
    }

    public void setAnimals(List<Animal> list) {
        this.animals = list;
    }

    public List<Animal> getAnimals() {
        return this.animals;
    }

}