Here you can find the source of toString(Collection
public static String toString(Collection<Object> collection)
//package com.java2s; /**/*from w w w . j a v a2 s . co m*/ * Copyright 2012 Red Hat, Inc. and/or its affiliates. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301 USA */ import java.util.Collection; public class Main { public static String toString(Collection<Object> collection) { if (collection == null) { return ""; } StringBuilder builder = new StringBuilder(); for (Object item : collection) { if (item == null) { continue; } builder.append(String.valueOf(item)); } return builder.toString(); } }