Here you can find the source of joinString(Collection
public static String joinString(Collection<String> values, String delimiter)
//package com.java2s; /******************************************************************************* * Copyright 2013 Khepry Software//from www . j a v a2 s . c om * * Licensed 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; import java.util.List; public class Main { public static String joinString(Collection<String> values, String delimiter) { StringBuilder sb = new StringBuilder(); for (String value : values) { sb.append(value); sb.append(delimiter); } if (sb.length() >= delimiter.length()) { sb.setLength(sb.length() - delimiter.length()); } return sb.toString(); } public static String joinString(List<String> values, String delimiter) { StringBuilder sb = new StringBuilder(); for (String value : values) { sb.append(value); sb.append(delimiter); } if (sb.length() >= delimiter.length()) { sb.setLength(sb.length() - delimiter.length()); } return sb.toString(); } public static String joinString(String[] values, String delimiter) { StringBuilder sb = new StringBuilder(); for (String value : values) { sb.append(value); sb.append(delimiter); } if (sb.length() >= delimiter.length()) { sb.setLength(sb.length() - delimiter.length()); } return sb.toString(); } }