gistfile1.java

public class ProductCatalogue {
  private Multimap<Class, ? extends Item> catalogue = ArrayListMultimap.create();

  public void add(Item item) {
    catalogue.put(item.getClass(), item);
  }

  public <T extends Item> Collection<Item> list(Class<T> clazz) {
    return catalogue.get(clazz);
  }
}

ProductCatalogue catalogue = new ProductCatalogue();
catalogue.add(new Book("1", "Book1"));
catalogue.add(new Movie("2", "Movie1"));
// only get books
System.out.println("Books " + catalogue.list(Book.class));
// only get movies
System.out.println("Movies " + catalogue.list(Movie.class));