gistfile1.java

public class LazyListManagerUtils {

  public static <T> List<T> add(List<T> list, T item) {
		if (list == null) {
			list = new ArrayList<T>();
			list.add(item);
		}
		else if (!list.contains(item)) {
			list.add(item);
		}
		return list;
	}

	public static <T> List<T> remove(List<T> list, T item) {
		if (list != null) {
			list.remove(item);
			if (list.isEmpty()) {
				list = null;
			}
		}
		return list;
	}
}