Index: oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java	(revision 9ef9fde23d3d85b174e38fb320d6f758dad8bb7a)
+++ oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java	(revision )
@@ -102,7 +102,7 @@
                         if (change == STOP) {
                             return;
                         }
-                        observer.contentChanged(change.root, change.info);
+                        notifyObserver(observer, change);
                     }
                 } catch (InterruptedException e) {
                     getLogger(observer).warn(
@@ -115,6 +115,10 @@
         thread.setDaemon(true);
         thread.setUncaughtExceptionHandler(exceptionHandler);
         thread.start();
+    }
+
+    private synchronized  void notifyObserver(Observer observer, ContentChange change) {
+        observer.contentChanged(change.root, change.info);
     }
 
     public BackgroundObserver(