From 913692f94724449ff6647bdddb074a705ca377e8 Mon Sep 17 00:00:00 2001
From: Michael Hirsch <michael.hirsch@bosch-si.com>
Date: Wed, 10 Aug 2016 09:22:57 +0200
Subject: [PATCH] lock session on error showing error notification

Signed-off-by: Michael Hirsch <michael.hirsch@bosch-si.com>
---
 .../hawkbit/ui/components/HawkbitUIErrorHandler.java     | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/components/HawkbitUIErrorHandler.java b/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/components/HawkbitUIErrorHandler.java
index 7729b72a4..bd56aba42 100644
--- a/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/components/HawkbitUIErrorHandler.java
+++ b/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/components/HawkbitUIErrorHandler.java
@@ -21,6 +21,7 @@ import com.google.common.base.Optional;
 import com.vaadin.server.DefaultErrorHandler;
 import com.vaadin.server.ErrorEvent;
 import com.vaadin.server.Page;
+import com.vaadin.server.VaadinSession;
 import com.vaadin.ui.Component;
 
 /**
@@ -40,7 +41,13 @@ public class HawkbitUIErrorHandler extends DefaultErrorHandler {
 
         if (originError.isPresent()) {
             final HawkbitErrorNotificationMessage message = buildNotification(getRootExceptionFrom(event));
-            message.show(originError.get());
+            final VaadinSession current = VaadinSession.getCurrent();
+            current.lock();
+            try {
+                message.show(originError.get());
+            } finally {
+                current.unlock();
+            }
         }
     }