Here you can find the source of sum(final Iterable
public static long sum(final Iterable<Long> ns)
//package com.java2s; /*// w ww . j a va2s .c o m * Copyright (c) 2014 Vincent W. Chen. * * This file is part of XJavaB. * * XJavaB is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * XJavaB 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with XJavaB. If not, see <http://www.gnu.org/licenses/>. */ public class Main { public static long sum(final Iterable<Long> ns) { long res = 0; for (final long n : ns) { res += n; } return res; } }