--- a/src/share/classes/com/sun/corba/se/impl/protocol/CorbaClientRequestDispatcherImpl.java	Tue Dec 13 17:19:28 2011 -0800
+++ b/src/share/classes/com/sun/corba/se/impl/protocol/CorbaClientRequestDispatcherImpl.java	Wed Dec 28 01:18:48 2011 +0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2011, 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
@@ -113,6 +113,9 @@
 import com.sun.corba.se.impl.transport.CorbaContactInfoListIteratorImpl;
 import com.sun.corba.se.impl.util.JDKBridge;
 
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ConcurrentHashMap;
+
 /**
  * ClientDelegate is the RMI client-side subcontract or representation
  * It implements RMI delegate as well as our internal ClientRequestDispatcher
@@ -122,6 +125,9 @@
     implements
         ClientRequestDispatcher
 {
+    private ConcurrentMap<ContactInfo, Object> locks =
+            new ConcurrentHashMap<ContactInfo, Object>();
+
     public OutputObject beginRequest(Object self, String opName,
                                      boolean isOneWay, ContactInfo contactInfo)
     {
@@ -148,8 +154,21 @@
 
         // This locking is done so that multiple connections are not created
         // for the same endpoint
-        //6929137 - Synchronized on contactInfo to avoid blocking across multiple endpoints
-        synchronized (contactInfo) {
+        // 7046238 - Synchronization on a single monitor for contactInfo parameters
+        // with identical hashCode(), so we lock on same monitor for equal parameters
+        // (which can refer to equal (in terms of equals()) but not the same objects)
+
+        Object lock = locks.get(contactInfo);
+
+        if (lock == null) {
+            Object newLock = new Object();
+            lock = locks.putIfAbsent(contactInfo, newLock);
+            if (lock == null) {
+                lock = newLock;
+            }
+        }
+
+        synchronized (lock) {
             if (contactInfo.isConnectionBased()) {
                 if (contactInfo.shouldCacheConnection()) {
                     connection = (CorbaConnection)
@@ -254,7 +273,7 @@
         registerWaiter(messageMediator);
 
         // Do connection reclaim now
-        synchronized (contactInfo) {
+        synchronized (lock) {
             if (contactInfo.isConnectionBased()) {
                 if (contactInfo.shouldCacheConnection()) {
                     OutboundConnectionCache connectionCache =