Java tutorial
//package com.java2s; import java.util.ArrayList; import java.util.Collection; public class Main { /** * @return all the elements of first without any of those in second */ public static <E> Collection<E> less(Collection<E> first, Collection<E> second) { Collection<E> accum = new ArrayList<E>(first); for (E e : second) { accum.remove(e); } return accum; } }