### Eclipse Workspace Patch 1.0
#P jackrabbit-core-2.2
Index: src/main/java/org/apache/jackrabbit/core/data/GarbageCollector.java
===================================================================
--- src/main/java/org/apache/jackrabbit/core/data/GarbageCollector.java	(revision 1350183)
+++ src/main/java/org/apache/jackrabbit/core/data/GarbageCollector.java	(working copy)
@@ -76,7 +76,7 @@
 public class GarbageCollector implements DataStoreGarbageCollector {
 
     /** logger instance */
-    private static final Logger LOG = LoggerFactory.getLogger(GarbageCollector.class);
+    static final Logger LOG = LoggerFactory.getLogger(GarbageCollector.class);
 
     private MarkEventListener callback;
 
@@ -98,6 +98,9 @@
 
     private boolean persistenceManagerScan;
 
+    private volatile RepositoryException observationException;
+
+
     /**
      * Create a new garbage collector.
      * This method is usually not called by the application, it is called
@@ -178,7 +181,7 @@
 
         // add a listener to get 'new' nodes
         // actually, new nodes are not the problem, but moved nodes
-        listeners.add(new Listener(session));
+        listeners.add(new Listener(this, session));
 
         // adding a link to a BLOB updates the modified date
         // reading usually doesn't, but when scanning, it does
@@ -234,14 +237,11 @@
     public void stopScan() throws RepositoryException {
         if (listeners.size() > 0) {
             for (Listener listener : listeners) {
-                try {
-                    listener.stop();
-                } catch (Exception e) {
-                    throw new RepositoryException(e);
-                }
+                listener.stop();
             }
             listeners.clear();
         }
+        checkObservationException();
     }
 
     /**
@@ -309,6 +309,7 @@
         } catch (InvalidItemStateException e) {
             LOG.debug("Node removed concurrently - ignoring", e);
         }
+        checkObservationException();
     }
 
     private void rememberNode(String path) {
@@ -368,6 +369,24 @@
         }
     }
 
+    private void checkObservationException() throws RepositoryException {
+        RepositoryException e = observationException;
+        if (e != null) {
+            observationException = null;
+            String message = "Exception while processing concurrent events";
+            LOG.warn(message, e);
+            e = new RepositoryException(message, e);
+        }
+    }
+
+    void onObservationException(Exception e) {
+        if (e instanceof RepositoryException) {
+            observationException = (RepositoryException) e;
+        } else {
+            observationException = new RepositoryException(e);
+        }
+    }
+
     /**
      * Auto-close in case the application didn't call it explicitly.
      */
@@ -382,26 +401,23 @@
      */
     class Listener implements SynchronousEventListener {
 
+        private final GarbageCollector gc;
         private final Session session;
-
         private final ObservationManager manager;
 
-        private Exception lastException;
-
-        Listener(Session session)
+        Listener(GarbageCollector gc, Session session)
                 throws UnsupportedRepositoryOperationException,
                 RepositoryException {
+            this.gc = gc;
             this.session = session;
             Workspace ws = session.getWorkspace();
             manager = ws.getObservationManager();
+            // Event.NODE_ADDED also includes moved nodes
             manager.addEventListener(this, Event.NODE_ADDED, "/", true, null,
                     null, false);
         }
 
-        void stop() throws Exception {
-            if (lastException != null) {
-                throw lastException;
-            }
+        void stop() throws RepositoryException {
             manager.removeEventListener(this);
         }
 
@@ -427,7 +443,12 @@
                         // ignore
                     }
                 } catch (Exception e) {
-                    lastException = e;
+                    gc.onObservationException(e);
+                    try {
+                        stop();
+                    } catch (RepositoryException e2) {
+                        LOG.warn("Exception removing the observation listener - ignored", e2);
+                    }
                 }
             }
         }