Creating References Using Inheritance Hierarchies

public class Item {}
public class Book extends Item {
    public String title() { return "Book"; }
}
public class Toy extends Item {
    public String name() { return "Toy"; }
}
public static String describe(Item i) {
    if (i instanceof Book) return ((Book) i).title();
    if (i instanceof Toy) return ((Toy) i).name();
    return "?";
}
// Usage:
System.out.print(describe(new Toy()));

• A

  Book

• B

  ?

• C

  ClassCastException

• D

  Toy

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