Here you can find the source of toCharArray(String s)
private static char[] toCharArray(String s)
//package com.java2s; /*// ww w.j ava2s . c o m * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores * CA 94065 USA or visit www.oracle.com if you need additional information or * have any questions. */ public class Main { private static boolean charArrayBugTested; private static boolean charArrayBug; private static char[] toCharArray(String s) { // toCharArray should return a new array always, however some devices might // suffer a bug that allows mutating a String (serious security hole in the JVM) // hence this method simulates the proper behavior if (!charArrayBugTested) { charArrayBugTested = true; if (s.toCharArray() == s.toCharArray()) { charArrayBug = true; } } if (charArrayBug) { char[] c = new char[s.length()]; System.arraycopy(s.toCharArray(), 0, c, 0, c.length); return c; } return s.toCharArray(); } }