I need assistance with polymorphis and interface in my project

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Let’s walk through the instructions.

  1. Add at least one of each of your new animal types to the zoo in ZooTest.java

This would require implementing your interface in a subclass of Animal and adding an instance of it to the zoo list. e.g.

List<? extends Animal> zoo = new ArrayList<>();
zoo.add(new Fox());
zoo.add(new Dog());
zoo.add(new Bear());
// plus more?
  1. Create an array or ArrayList of Pets

Simple enough. Create a list with Pet as the type. A list makes more sense for this situation.

List<Pet> pets = new ArrayList<>();
  1. Loop through the zoo. If an animal is also a pet, add it to the pet array

In order to determine if an object is of a certain type, we can use the instanceof keyword. After that check, we can safely cast to the desired type.

if (animal instanceof Pet)
    pets.add((Peg) animal);
  1. Iterate through the pet array (which should only have pets) and have each pet do something that

Seems fairly obvious. Iterate the pets list.

for (Pet pet : pets) {
    ...
}

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