Here you can find the source of join(String joiner, String... toJoin)
public static String join(String joiner, String... toJoin)
//package com.java2s; /**/*from w w w . j av a2 s . c om*/ * LICENSING * * This software is copyright by sunkid <sunkid@iminurnetz.com> and is * distributed under a dual license: * * Non-Commercial Use: * This program 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. * * This program 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 this program. If not, see <http://www.gnu.org/licenses/>. * * Commercial Use: * Please contact sunkid@iminurnetz.com */ import java.util.Arrays; import java.util.List; public class Main { public static String join(String joiner, String... toJoin) { return join(joiner, Arrays.asList(toJoin), 0); } public static String join(String joiner, List<String> toJoin, int start) { if (isEmpty(joiner) || toJoin == null || toJoin.size() <= start) return ""; StringBuilder result = new StringBuilder(); for (int n = start; n < toJoin.size(); n++) { result.append(toJoin.get(n)); result.append(joiner); } return result.substring(0, result.length() - joiner.length()); } public static String join(String joiner, String[] toJoin, int start) { return join(joiner, Arrays.asList(toJoin), start); } public static boolean isEmpty(String string) { return (string == null || string.equals("")); } }