Here you can find the source of addAll(Collection
public static <T> void addAll(Collection<T> collection, T[] array)
//package com.java2s; //License from project: Open Source License import java.util.Collection; public class Main { public static <T> void addAll(Collection<T> target, Iterable<? extends T> source) { for (T e : source) target.add(e);/*w w w . j av a 2 s . c om*/ } public static <T> void addAll(Collection<T> collection, T[] array) { for (int i = 0; i < array.length; ++i) collection.add(array[i]); } }