1 files changed, 20 insertions, 18 deletions
diff --git a/src/com/vaadin/terminal/gwt/server/AbstractWebApplicationContext.java b/src/com/vaadin/terminal/gwt/server/AbstractWebApplicationContext.java
index bcac87e6ad..92488ef9ca 100644
--- a/src/com/vaadin/terminal/gwt/server/AbstractWebApplicationContext.java
+++ b/src/com/vaadin/terminal/gwt/server/AbstractWebApplicationContext.java
@@ -3,22 +3,22 @@
  */
 package com.vaadin.terminal.gwt.server;
 
-import java.io.PrintWriter;
-import java.io.Serializable;
-import java.io.StringWriter;
-import java.net.URL;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedList;
-
-import javax.servlet.http.HttpSessionBindingEvent;
-import javax.servlet.http.HttpSessionBindingListener;
-
-import com.vaadin.Application;
-import com.vaadin.service.ApplicationContext;
-import com.vaadin.terminal.ApplicationResource;
+import java.io.PrintWriter;
+import java.io.Serializable;
+import java.io.StringWriter;
+import java.net.URL;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
+
+import javax.servlet.http.HttpSessionBindingEvent;
+import javax.servlet.http.HttpSessionBindingListener;
+
+import com.vaadin.Application;
+import com.vaadin.service.ApplicationContext;
+import com.vaadin.terminal.ApplicationResource;
 
 /**
  * Base class for web application contexts (including portlet contexts) that
@@ -36,8 +36,10 @@ public abstract class AbstractWebApplicationContext implements
 
     protected HashMap<Application, AbstractCommunicationManager> applicationToAjaxAppMgrMap = new HashMap<Application, AbstractCommunicationManager>();
 
-    public void addTransactionListener(TransactionListener listener) {
-        listeners.add(listener);
+    public void addTransactionListener(TransactionListener listener) {
+        if (listener != null) {
+            listeners.add(listener);
+        }
     }
 
     public void removeTransactionListener(TransactionListener listener) {