Polymorphism

We already know that polymorphism means different forms. But what does it mean to us?

Boiled down to its simplest:

Any subclass can be used as part of the code that uses the super class.

This means we can write code that is simpler and easier to understand, and easier to change.

Also, we can write code for the super class and rely on the fact that no matter how many times it is sub-classed, within certain parameters, the code will still work. Let's discuss an example.

Suppose we want to use polymorphism to help to write a zoo management app. We will probably want to have a method such as feed. We will probably want to pass a reference to the animal to be fed into the feed method. This might seem like we need to write a feed method for each and every type of Animal.

However, we can write polymorphic methods with polymorphic return types and arguments:

Animal feed(Animal animalToFeed){
   // Feed any animal here
   ...