Polymorphism

ArrayList<BoxBug> boxbugs;ArrayList<Critter> critters;ArrayList<KingCrab> kingCrabs;ArrayList<WorkerAnt> workerants;

boxbugs.get(i).act();critters.get(i).act();kingCrabs.get(i).act();workerants.get(i).act();

ArrayList<Actor> actors;

actors.get(i).act();

Java correctly decides which type

of actor it is and calls the

corresponding act() method. All

actors act differently, even though

they are all being stored as plain

old Actors.

What’s required for polymorphism to work? Actor

Bug

BoxBug ZBug

Critter

RockHound

Actor a = new BoxBug(4);a.act();

act();

act();

act(); act();

act();

act();

getActors()

getActors()

BoxBugs act() called

Actor a = new RockHound();a.getActors();

No getActors() method!!!!

ERROR!!!