Here you can find the source of join(Collection strings, String separator)
public static String join(Collection<?> strings, String separator)
//package com.java2s; /*/*w ww . j a v a2s . c om*/ * * * ProActive Parallel Suite(TM): The Java(TM) library for * Parallel, Distributed, Multi-Core Computing for * Enterprise Grids & Clouds * * Copyright (C) 1997-2015 INRIA/University of * Nice-Sophia Antipolis/ActiveEon * Contact: proactive@ow2.org or contact@activeeon.com * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Affero General Public License * as published by the Free Software Foundation; version 3 of * the License. * * This library 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 * Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 * USA * * If needed, contact us to obtain a release under GPL Version 2 or 3 * or a different license than the AGPL. * * Initial developer(s): The ProActive Team * http://proactive.inria.fr/team_members.htm * Contributor(s): * * * $$ACTIVEEON_INITIAL_DEV$$ */ import java.util.Collection; public class Main { /** * Concatenate multiple strings by inserting a separator. */ public static String join(Collection<?> strings, String separator) { StringBuilder buf = new StringBuilder(); boolean first = true; for (Object s : strings) { if (first) first = false; else buf.append(separator); buf.append(s); } return buf.toString(); } }