Index: /trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/manager/TaskTreeManager.java
===================================================================
--- /trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/manager/TaskTreeManager.java	(revision 2235)
+++ /trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/manager/TaskTreeManager.java	(revision 2236)
@@ -187,5 +187,5 @@
      * @param event the event to handle
      */
-    public void handleNewEvent(Event event) {
+    public synchronized void handleNewEvent(Event event) {
         assertSessionSequence();
         
@@ -216,5 +216,5 @@
      * </p>
      */
-    public void finishSession() {
+    public synchronized void finishSession() {
         if ((currentSession != null) && (currentSession.size() > 0)) {
             sessions.add(currentSession);