--- a/jdk/src/share/classes/java/util/Calendar.java	Tue Jan 24 15:13:27 2012 -0500
+++ b/jdk/src/share/classes/java/util/Calendar.java	Thu Jan 26 17:06:47 2012 +0900
@@ -2705,7 +2705,7 @@
      * removed from the serialization stream; this will probably happen in the
      * near future.
      */
-    private void writeObject(ObjectOutputStream stream)
+    private synchronized void writeObject(ObjectOutputStream stream)
          throws IOException
     {
         // Try to compute the time correctly, for the future (stream

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/Calendar/Bug7017458.java	Thu Jan 26 17:06:47 2012 +0900
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2012, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 7017458
+ * @summary Test of multithreaded serialization/deserialization of Calendar.
+ */
+
+import java.io.*;
+import java.util.Calendar;
+
+public class Bug7017458 {
+
+    static volatile boolean err = false;
+
+    public static void main(String[] args) {
+        try {
+            new Bug7017458().perform();
+        }
+        catch (Exception e) {
+            e.printStackTrace();
+            err = true;
+        }
+
+        if (err) {
+            throw new RuntimeException("Multithreaded serialization/deserialization test failed.");
+        } else {
+            System.out.println("Multithreaded serialization/deserialization test passed.");
+        }
+    }
+
+    public void perform() throws Exception {
+        int nbThreads = 8;
+        Calendar cal = Calendar.getInstance();
+        SerializationThread[] threads = new SerializationThread[nbThreads];
+        for (int i = 0; i < nbThreads; i++) {
+            threads[i] = new SerializationThread(cal);
+        }
+        for (int i = 0; i < nbThreads; i++) {
+            threads[i].start();
+        }
+        for (int i = 0; i < nbThreads; i++) {
+            threads[i].join();
+        }
+
+        DeserializationThread[] threads2 = new DeserializationThread[nbThreads];
+        for (int i = 0; i < nbThreads; i++) {
+            threads2[i] = new DeserializationThread(threads[i].data);
+        }
+        for (int i = 0; i < nbThreads; i++) {
+            threads2[i].start();
+        }
+        for (int i = 0; i < nbThreads; i++) {
+            threads2[i].join();
+        }
+    }
+
+    public class SerializationThread extends Thread {
+        private Calendar cal;
+        public byte[] data;
+
+        public SerializationThread(Calendar cal) {
+            this.cal = cal;
+        }
+
+        public void run() {
+            try {
+                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                ObjectOutputStream oos = new ObjectOutputStream(baos);
+                oos.writeObject(cal);
+                oos.flush();
+                oos.close();
+                data = baos.toByteArray();
+                }
+            catch (Exception e) {
+                e.printStackTrace();
+                err = true;
+            }
+        }
+    }
+
+    public class DeserializationThread extends Thread {
+        public Calendar cal;
+        public byte[] data;
+
+        public DeserializationThread(byte[] data) {
+            this.data = data;
+        }
+
+        public void run() {
+            try {
+                ByteArrayInputStream bais = new ByteArrayInputStream(data);
+                ObjectInputStream ois = new ObjectInputStream(bais);
+                cal = (Calendar) ois.readObject();
+                ois.close();
+            }
+            catch (Exception e) {
+                e.printStackTrace();
+                err = true;
+            }
+        }
+    }
+}
+