--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/ConcurrentModificationException.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,86 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.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 <tt>ConcurrentModificationException</tt> on a best-effort basis.
+ * Therefore, it would be wrong to write a program that depended on this
+ * exception for its correctness: <i><tt>ConcurrentModificationException</tt>
+ * should be used only to detect bugs.</i>
+ *
+ * @author  Josh Bloch
+ * @see     Collection
+ * @see     Iterator
+ * @see     ListIterator
+ * @see     Vector
+ * @see     LinkedList
+ * @see     HashSet
+ * @see     Hashtable
+ * @see     TreeMap
+ * @see     AbstractList
+ * @since   1.2
+ */
+public class ConcurrentModificationException extends RuntimeException {
+    /**
+     * Constructs a ConcurrentModificationException with no
+     * detail message.
+     */
+    public ConcurrentModificationException() {
+    }
+
+    /**
+     * Constructs a <tt>ConcurrentModificationException</tt> with the
+     * specified detail message.
+     *
+     * @param message the detail message pertaining to this exception.
+     */
+    public ConcurrentModificationException(String message) {
+        super(message);
+    }
+}