Could you explain polymorphism in Java in a simple way?

Question

I’m learning about abstract classes and polymorphism and it’s brand new concepts (pretty hard ones at that ahah) and just wanted to know if anyone here had a good/basic/fun way to explain it?

Answer 1

Polymorphism basically means that one thing can be or do different things. It comes in lots of different forms. In Java you'll usually encounter

# Subtyping:

class Animal { }
class Dog extends Animal { }

now you can use a "Dog" for any function that needs an "Animal", like this

public void iWantAnAnimal(Animal a) { }

iWantAnAnimal(new Dog());

# Ad-Hoc Polymorphism (overloading):

That's when a function does multiple things depending on type.

public Integer doubleMe(Integer i) { return i + i; }
public String doubleMe(String i) { return i.concat(i); }

There's lots of other types of polymorphism, those are the main ones found in Java though. Hope that helps!