<code lang="Java">
import java.util.*;

class RemoveDoubles {
	
	public static void main(String[] args) {
		List<String> animals = new ArrayList<String>();
		animals.add("Horse");
		animals.add("Crocodile");
		animals.add("Cat");
		animals.add("Hamster");
		animals.add("Cat");
		animals.add("Cat");
		animals.add("Crocodile");
		animals.add("Mouse");
		animals.add("Elk");
		System.out.println(animals);
		removeDoubles(animals);
		System.out.println(animals);
	}
	
	public static <E, T extends List<E>> T removeDoubles(T list) {
		Iterator<E> it = list.iterator();
		Set<E> s = new HashSet<E>();
		while (it.hasNext()) {
			E elem = it.next();
			if (!s.add(elem)) {
				it.remove();
			}
		}
		return list;
	}
}
</code>