Here you can find the source of join(Iterable target, String separator)
public static String join(Iterable<?> target, String separator)
//package com.java2s; /*/* w w w. ja v a 2 s . co m*/ * [The "BSD licence"] * Copyright (c) 2013-2015 Dandelion * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of Dandelion nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ import java.util.Iterator; public class Main { public static String join(Object[] target, String separator) { final StringBuilder sb = new StringBuilder(); if (target.length > 0) { sb.append(target[0]); for (int i = 1; i < target.length; i++) { sb.append(separator); sb.append(target[i]); } } return sb.toString(); } public static String join(Iterable<?> target, String separator) { StringBuilder sb = new StringBuilder(); Iterator<?> it = target.iterator(); if (it.hasNext()) { sb.append(it.next()); while (it.hasNext()) { sb.append(separator); sb.append(it.next()); } } return sb.toString(); } }