import java.util.ArrayList;

public class ArrayListTypesDemo {

static abstract class Gnome {

public String name;

public Gnome(String name) {

this.name = name;

}

}

static class GardenGnome extends Gnome {

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

}

static class UnderwearGnome extends Gnome {

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

}

public static void main(String[] args) {

ArrayList<Gnome> gnomes = new ArrayList<>();

ArrayList<GardenGnome> gardenGnomes = new ArrayList<>();

ArrayList<UnderwearGnome> underwearGnomes = new ArrayList<>();

// Fine: Gnome is a superclass

gnomes.add(new GardenGnome("Corny"));

gnomes.add(new UnderwearGnome("Jaques"));

// Nuh, uh! Type incompatibility.

underwearGnomes.add(new GardenGnome("Carrot Top"));

}

}