Here you can find the source of toString(Collection> collection)
public static String toString(Collection<?> collection)
//package com.java2s; /*//from w ww . j av a2s. c o m * Copyright 2011-2013 the original author or authors. * * 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; public class Main { public static String toString(Collection<?> collection) { StringBuilder sb = new StringBuilder(collection.size() * 2); for (Object item : collection) { sb.append(item).append(","); } // sb.deleteCharAt(sb.lastIndexOf(",")); return sb.toString(); } }