01: /*
02: * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
03: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04: *
05: * This code is free software; you can redistribute it and/or modify it
06: * under the terms of the GNU General Public License version 2 only, as
07: * published by the Free Software Foundation. Sun designates this
08: * particular file as subject to the "Classpath" exception as provided
09: * by Sun in the LICENSE file that accompanied this code.
10: *
11: * This code is distributed in the hope that it will be useful, but WITHOUT
12: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14: * version 2 for more details (a copy is included in the LICENSE file that
15: * accompanied this code).
16: *
17: * You should have received a copy of the GNU General Public License version
18: * 2 along with this work; if not, write to the Free Software Foundation,
19: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20: *
21: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22: * CA 95054 USA or visit www.sun.com if you need additional information or
23: * have any questions.
24: */
25:
26: package java.util;
27:
28: /**
29: * This exception may be thrown by methods that have detected concurrent
30: * modification of an object when such modification is not permissible.
31: * <p>
32: * For example, it is not generally permissible for one thread to modify a Collection
33: * while another thread is iterating over it. In general, the results of the
34: * iteration are undefined under these circumstances. Some Iterator
35: * implementations (including those of all the general purpose collection implementations
36: * provided by the JRE) may choose to throw this exception if this behavior is
37: * detected. Iterators that do this are known as <i>fail-fast</i> iterators,
38: * as they fail quickly and cleanly, rather that risking arbitrary,
39: * non-deterministic behavior at an undetermined time in the future.
40: * <p>
41: * Note that this exception does not always indicate that an object has
42: * been concurrently modified by a <i>different</i> thread. If a single
43: * thread issues a sequence of method invocations that violates the
44: * contract of an object, the object may throw this exception. For
45: * example, if a thread modifies a collection directly while it is
46: * iterating over the collection with a fail-fast iterator, the iterator
47: * will throw this exception.
48: *
49: * <p>Note that fail-fast behavior cannot be guaranteed as it is, generally
50: * speaking, impossible to make any hard guarantees in the presence of
51: * unsynchronized concurrent modification. Fail-fast operations
52: * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
53: * Therefore, it would be wrong to write a program that depended on this
54: * exception for its correctness: <i><tt>ConcurrentModificationException</tt>
55: * should be used only to detect bugs.</i>
56: *
57: * @author Josh Bloch
58: * @version 1.26, 05/05/07
59: * @see Collection
60: * @see Iterator
61: * @see ListIterator
62: * @see Vector
63: * @see LinkedList
64: * @see HashSet
65: * @see Hashtable
66: * @see TreeMap
67: * @see AbstractList
68: * @since 1.2
69: */
70: public class ConcurrentModificationException extends RuntimeException {
71: /**
72: * Constructs a ConcurrentModificationException with no
73: * detail message.
74: */
75: public ConcurrentModificationException() {
76: }
77:
78: /**
79: * Constructs a <tt>ConcurrentModificationException</tt> with the
80: * specified detail message.
81: *
82: * @param message the detail message pertaining to this exception.
83: */
84: public ConcurrentModificationException(String message) {
85: super(message);
86: }
87: }
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