Here you can find the source of join(List> resultList, String sep)
public static String join(List<?> resultList, String sep)
//package com.java2s; /**/* w w w. j a va 2s . c om*/ * Copyright 2013 markiewb * * 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.List; public class Main { public static String join(List<?> resultList, String sep) { if (null == resultList) { return ""; } if (resultList.isEmpty()) { return ""; } StringBuilder sb = new StringBuilder(); for (int i = 0; i < resultList.size(); i++) { Object item = resultList.get(i); if (i > 0) { sb.append(sep); } sb.append(item.toString()); } return sb.toString(); } }