Java tutorial
//package com.java2s; //License from project: Open Source License import java.util.Collection; import java.util.HashSet; import java.util.Set; public class Main { public static <T> Set<T> union(Collection<? extends T> c1, Collection<? extends T> c2) { Set<T> result = new HashSet<T>(); result.addAll(c1); result.addAll(c2); return result; } public static <T> void addAll(Collection<T> target, Iterable<? extends T> source) { for (T e : source) target.add(e); } public static <T> void addAll(Collection<T> collection, T[] array) { for (int i = 0; i < array.length; ++i) collection.add(array[i]); } }