Avoid ConcurrentModificationException when accessing the PerformanceQueues page while yacy is indexing.

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@4170 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/plasma/plasmaWordIndex.java

@@ -131,12 +131,14 @@ public final class plasmaWordIndex implements indexRI {
         long cacheBytes = 0;
         long entryBytes = indexRWIEntry.urlEntryRow.objectsize();
         indexRAMRI cache = (in ? dhtInCache : dhtOutCache);
+        synchronized (cache) {
             Iterator it = cache.wordContainers(null, false);
             indexContainer ic;
             while ( it.hasNext() ) {
                 ic = (indexContainer)it.next();
                 cacheBytes += ic.size() * entryBytes;
             }
+        }
         
         return cacheBytes;
     }