Here you can find the source of toArray(Iterable
public static <T> T[] toArray(Iterable<T> elements)
//package com.java2s; /*// w w w .j a v a 2s . c o m * Copyright (c) 2012 Rice University. * * This file is part of PhyloNet. * * PhyloNet is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * PhyloNet is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with PhyloNet. If not, see <http://www.gnu.org/licenses/>. */ import java.util.*; public class Main { public static <T> T[] toArray(Iterable<T> elements) { LinkedList<T> accum = new LinkedList<T>(); for (T element : elements) { accum.add(element); } return (T[]) accum.toArray(); } }