Here you can find the source of join(String sep, Object[] os)
public static String join(String sep, Object[] os)
//package com.java2s; /*/*from w w w. ja v a 2s . c o m*/ * Copyright (C) 2015 Stefan Niederhauser (nidin@gmx.ch) * * 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.Arrays; import java.util.List; public class Main { public static String join(String sep, Object[] os) { return join(sep, Arrays.asList(os)); } public static String join(String sep, List<?> os) { final StringBuilder res = new StringBuilder(); for (final Object o : os) { res.append(sep).append(o); } return os.isEmpty() ? "" : res.substring(sep.length()); } }