Index: PortletWindowSessionNavigationalStates.java
===================================================================
--- PortletWindowSessionNavigationalStates.java	(revision 667491)
+++ PortletWindowSessionNavigationalStates.java	(working copy)
@@ -17,6 +17,7 @@
 package org.apache.jetspeed.container.state.impl;
 
 import java.io.Serializable;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -36,7 +37,7 @@
 {
     private static final class PageState implements Serializable
     {
-        public Map windowStates = new HashMap();
+        public Map windowStates = Collections.synchronizedMap( new HashMap() );
         public String maximizedWindowId;
     }
     
@@ -77,47 +78,48 @@
             pageState.maximizedWindowId = null;
         }
 
-        Iterator iter = requestStates.getWindowIdIterator();
-        iter = pageState.windowStates.keySet().iterator();
-        String windowId;
-        while ( iter.hasNext() )
-        {
-            windowId = (String)iter.next();
-            requestState = requestStates.getPortletWindowNavigationalState(windowId);
-            if ( requestState == null )
-            {
-                requestState = new PortletWindowRequestNavigationalState(windowId);
-            }
-            //regardless, reset portlet mode and window state
-            requestState.setPortletMode(viewMode);
-            requestState.setWindowState(normalWindowState);
-            // get the session case just in case and create a new one
-            sessionState = (PortletWindowBaseNavigationalState)pageState.windowStates.get(requestState.getWindowId());
-            if ( sessionState == null )
-            {
-                if ( storeParameters )
-                {
-                    sessionState = new PortletWindowExtendedNavigationalState();
-                }
-                else
-                {
-                    sessionState = new PortletWindowBaseNavigationalState();
-                }
-                pageState.windowStates.put(requestState.getWindowId(),sessionState);
-            }
-            //Now, sync up. NOTE we should not be in this method if there is an portlet action request.
-            boolean changed = syncStates(false, requestState,(PortletWindowBaseNavigationalState)pageState.windowStates.get(windowId));
-            if (changed)
-            {
-                removeFromCache(context, requestState.getWindowId(), cache);
-                removeFromCache(context, page.getId(), decorationCache);                    
-                if (storeParameters)
-                {
-                    ((PortletWindowExtendedNavigationalState)sessionState).resetDecoratorActionEncodings();
-                }
-            }
-            
-        }        
+        synchronized (pageState.windowStates) {
+        	Iterator iter = pageState.windowStates.keySet().iterator();
+	        String windowId;
+	        while ( iter.hasNext() )
+	        {
+	            windowId = (String)iter.next();
+	            requestState = requestStates.getPortletWindowNavigationalState(windowId);
+	            if ( requestState == null )
+	            {
+	                requestState = new PortletWindowRequestNavigationalState(windowId);
+	            }
+	            //regardless, reset portlet mode and window state
+	            requestState.setPortletMode(viewMode);
+	            requestState.setWindowState(normalWindowState);
+	            // get the session case just in case and create a new one
+	            sessionState = (PortletWindowBaseNavigationalState)pageState.windowStates.get(requestState.getWindowId());
+	            if ( sessionState == null )
+	            {
+	                if ( storeParameters )
+	                {
+	                    sessionState = new PortletWindowExtendedNavigationalState();
+	                }
+	                else
+	                {
+	                    sessionState = new PortletWindowBaseNavigationalState();
+	                }
+	                pageState.windowStates.put(requestState.getWindowId(),sessionState);
+	            }
+	            //Now, sync up. NOTE we should not be in this method if there is an portlet action request.
+	            boolean changed = syncStates(false, requestState,(PortletWindowBaseNavigationalState)pageState.windowStates.get(windowId));
+	            if (changed)
+	            {
+	                removeFromCache(context, requestState.getWindowId(), cache);
+	                removeFromCache(context, page.getId(), decorationCache);                    
+	                if (storeParameters)
+	                {
+	                    ((PortletWindowExtendedNavigationalState)sessionState).resetDecoratorActionEncodings();
+	                }
+	            }
+	            
+	        }
+        }
     }
     
     public void sync(RequestContext context, Page page, PortletWindowRequestNavigationalStates requestStates, JetspeedContentCache cache, JetspeedContentCache decorationCache)    
@@ -228,28 +230,30 @@
         }
         
         // now copy missing requestStates from the pageState
-        iter = pageState.windowStates.keySet().iterator();
-        String windowId;
-        while ( iter.hasNext() )
-        {
-            windowId = (String)iter.next();
-            requestState = requestStates.getPortletWindowNavigationalState(windowId);
-            if ( requestState == null )
-            {
-                requestState = new PortletWindowRequestNavigationalState(windowId);
-                boolean changed = syncStates(false, requestState,(PortletWindowBaseNavigationalState)pageState.windowStates.get(windowId));
-                requestStates.addPortletWindowNavigationalState(windowId, requestState);
-                if (changed)
-                {
-                    removeFromCache(context, requestState.getWindowId(), cache);
-                    removeFromCache(context, page.getId(), decorationCache);                    
-                    if (storeParameters)
-                    {
-                        ((PortletWindowExtendedNavigationalState)sessionState).resetDecoratorActionEncodings();
-                    }
-                }
-            }
-        }        
+        synchronized (pageState.windowStates) {
+	        iter = pageState.windowStates.keySet().iterator();
+	        String windowId;
+	        while ( iter.hasNext() )
+	        {
+	            windowId = (String)iter.next();
+	            requestState = requestStates.getPortletWindowNavigationalState(windowId);
+	            if ( requestState == null )
+	            {
+	                requestState = new PortletWindowRequestNavigationalState(windowId);
+	                boolean changed = syncStates(false, requestState,(PortletWindowBaseNavigationalState)pageState.windowStates.get(windowId));
+	                requestStates.addPortletWindowNavigationalState(windowId, requestState);
+	                if (changed)
+	                {
+	                    removeFromCache(context, requestState.getWindowId(), cache);
+	                    removeFromCache(context, page.getId(), decorationCache);                    
+	                    if (storeParameters)
+	                    {
+	                        ((PortletWindowExtendedNavigationalState)sessionState).resetDecoratorActionEncodings();
+	                    }
+	                }
+	            }
+	        }
+        }
     }
     
     private boolean modeChanged(PortletMode req, PortletMode ses)