Index: jetspeed-2/components/portal-site/src/java/org/apache/jetspeed/portalsite/impl/PortalSiteRequestContextImpl.java
===================================================================
--- jetspeed-2/components/portal-site/src/java/org/apache/jetspeed/portalsite/impl/PortalSiteRequestContextImpl.java	(revision 479959)
+++ jetspeed-2/components/portal-site/src/java/org/apache/jetspeed/portalsite/impl/PortalSiteRequestContextImpl.java	(working copy)
@@ -22,6 +22,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.Collections;
 
 import org.apache.jetspeed.om.folder.Folder;
 import org.apache.jetspeed.om.folder.MenuDefinition;
@@ -413,7 +414,7 @@
             if (locators != null)
             {
                 // get custom definition names
-                pageMenuDefinitionNames = new HashSet(locators.size());
+                pageMenuDefinitionNames = Collections.synchronizedSet(new HashSet(locators.size()));
                 Iterator locatorsIter = locators.iterator();
                 while (locatorsIter.hasNext())
                 {
@@ -427,7 +428,7 @@
             }
             else
             {
-                pageMenuDefinitionNames = new HashSet(0);
+                pageMenuDefinitionNames = Collections.synchronizedSet(new HashSet(0));
             }
         }
         return pageMenuDefinitionNames;
@@ -508,7 +509,7 @@
                     // cache relative menu for request
                     if (menuDefinitionLocatorCache == null)
                     {
-                        menuDefinitionLocatorCache = new HashMap(8);
+                        menuDefinitionLocatorCache = Collections.synchronizedMap(new HashMap(8));
                     }
                     menuDefinitionLocatorCache.put(locator, menu);
                 }
@@ -517,7 +518,7 @@
                     // cache absolute menu for session
                     if (sessionContext.getMenuDefinitionLocatorCache() == null)
                     {
-                        sessionContext.setMenuDefinitionLocatorCache(new HashMap(8));
+                        sessionContext.setMenuDefinitionLocatorCache(Collections.synchronizedMap(new HashMap(8)));
                     }
                     sessionContext.getMenuDefinitionLocatorCache().put(locator, menu);
                 }
Index: jetspeed-2/components/portal-site/src/java/org/apache/jetspeed/page/document/proxy/NodeProxy.java
===================================================================
--- jetspeed-2/components/portal-site/src/java/org/apache/jetspeed/page/document/proxy/NodeProxy.java	(revision 479959)
+++ jetspeed-2/components/portal-site/src/java/org/apache/jetspeed/page/document/proxy/NodeProxy.java	(working copy)
@@ -20,6 +20,7 @@
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Collections;
 
 import org.apache.jetspeed.om.folder.Folder;
 import org.apache.jetspeed.om.folder.MenuDefinition;
@@ -177,7 +178,7 @@
             List locators = getMenuDefinitionLocators();
             if (locators != null)
             {
-                menuDefinitions = new ArrayList(locators.size());
+                menuDefinitions = Collections.synchronizedList(new ArrayList(locators.size()));
                 Iterator locatorsIter = locators.iterator();
                 while (locatorsIter.hasNext())
                 {
@@ -260,7 +261,7 @@
                     {
                         if (menuDefinitionLocators == null)
                         {
-                            menuDefinitionLocators = new ArrayList(definitions.size() * 2);
+                            menuDefinitionLocators = Collections.synchronizedList(new ArrayList(definitions.size() * 2));
                         }
                         menuDefinitionLocators.add(new SiteViewMenuDefinitionLocator(definition, node));
                     }
@@ -295,7 +296,7 @@
                 {
                     if (menuDefinitionLocators == null)
                     {
-                        menuDefinitionLocators = new ArrayList(locators.size() * 2);
+                        menuDefinitionLocators = Collections.synchronizedList(new ArrayList(locators.size() * 2));
                     }
                     menuDefinitionLocators.add(locator);
                 }
@@ -326,13 +327,15 @@
         // find matching menu definition locator by name
         if ((menuDefinitionLocators != null) && (name != null))
         {
-            Iterator locatorsIter = menuDefinitionLocators.iterator();
-            while (locatorsIter.hasNext())
-            {
-                SiteViewMenuDefinitionLocator locator = (SiteViewMenuDefinitionLocator)locatorsIter.next();
-                if (name.equals(locator.getName()))
+            synchronized (menuDefinitionLocators) {
+                Iterator locatorsIter = menuDefinitionLocators.iterator();
+                while (locatorsIter.hasNext())
                 {
-                    return locator;
+                    SiteViewMenuDefinitionLocator locator = (SiteViewMenuDefinitionLocator)locatorsIter.next();
+                    if (name.equals(locator.getName()))
+                    {
+                        return locator;
+                    }
                 }
             }
         }