Java tutorial
/* * Copyright (c) 1997, 2013, 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. */ package java.util; /** * This exception may be thrown by methods that have detected concurrent * modification of an object when such modification is not permissible. * <p> * For example, it is not generally permissible for one thread to modify a Collection * while another thread is iterating over it. In general, the results of the * iteration are undefined under these circumstances. Some Iterator * implementations (including those of all the general purpose collection implementations * provided by the JRE) may choose to throw this exception if this behavior is * detected. Iterators that do this are known as <i>fail-fast</i> iterators, * as they fail quickly and cleanly, rather that risking arbitrary, * non-deterministic behavior at an undetermined time in the future. * <p> * Note that this exception does not always indicate that an object has * been concurrently modified by a <i>different</i> thread. If a single * thread issues a sequence of method invocations that violates the * contract of an object, the object may throw this exception. For * example, if a thread modifies a collection directly while it is * iterating over the collection with a fail-fast iterator, the iterator * will throw this exception. * * <p>Note that fail-fast behavior cannot be guaranteed as it is, generally * speaking, impossible to make any hard guarantees in the presence of * unsynchronized concurrent modification. Fail-fast operations * throw {@code ConcurrentModificationException} on a best-effort basis. * Therefore, it would be wrong to write a program that depended on this * exception for its correctness: <i>{@code ConcurrentModificationException} * should be used only to detect bugs.</i> * * @author Josh Bloch * @see Collection * @see Iterator * @see Spliterator * @see ListIterator * @see Vector * @see LinkedList * @see HashSet * @see Hashtable * @see TreeMap * @see AbstractList * @since 1.2 */ public class ConcurrentModificationException extends RuntimeException { private static final long serialVersionUID = -3666751008965953603L; /** * Constructs a ConcurrentModificationException with no * detail message. */ public ConcurrentModificationException() { } /** * Constructs a {@code ConcurrentModificationException} with the * specified detail message. * * @param message the detail message pertaining to this exception. */ public ConcurrentModificationException(String message) { super(message); } /** * Constructs a new exception with the specified cause and a detail * message of {@code (cause==null ? null : cause.toString())} (which * typically contains the class and detail message of {@code cause}. * * @param cause the cause (which is saved for later retrieval by the * {@link Throwable#getCause()} method). (A {@code null} value is * permitted, and indicates that the cause is nonexistent or * unknown.) * @since 1.7 */ public ConcurrentModificationException(Throwable cause) { super(cause); } /** * Constructs a new exception with the specified detail message and * cause. * * <p>Note that the detail message associated with <code>cause</code> is * <i>not</i> automatically incorporated in this exception's detail * message. * * @param message the detail message (which is saved for later retrieval * by the {@link Throwable#getMessage()} method). * @param cause the cause (which is saved for later retrieval by the * {@link Throwable#getCause()} method). (A {@code null} value * is permitted, and indicates that the cause is nonexistent or * unknown.) * @since 1.7 */ public ConcurrentModificationException(String message, Throwable cause) { super(message, cause); } }