Here you can find the source of join(Collection
public static String join(Collection<String> items, String prefix, String suffix, String itemPrefix, String itemSuffix)
//package com.java2s; /*/*from w w w . ja v a2 s . c om*/ * Copyright (c) 2016-2016 Vladimir Schneider <vladimir.schneider@gmail.com> * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ import java.util.Collection; public class Main { public static String join(String[] items, String prefix, String suffix, String itemPrefix, String itemSuffix) { StringBuilder sb = new StringBuilder(); sb.append(prefix); for (String item : items) { sb.append(itemPrefix).append(item).append(itemSuffix); } sb.append(suffix); return sb.toString(); } public static String join(Collection<String> items, String prefix, String suffix, String itemPrefix, String itemSuffix) { StringBuilder sb = new StringBuilder(); sb.append(prefix); for (String item : items) { sb.append(itemPrefix).append(item).append(itemSuffix); } sb.append(suffix); return sb.toString(); } }