diff --git a/smack-extensions/src/main/java/org/jivesoftware/smackx/pubsub/Node.java b/smack-extensions/src/main/java/org/jivesoftware/smackx/pubsub/Node.java
index cdf8e79b1..32946f486 100644
--- a/smack-extensions/src/main/java/org/jivesoftware/smackx/pubsub/Node.java
+++ b/smack-extensions/src/main/java/org/jivesoftware/smackx/pubsub/Node.java
@@ -699,12 +699,12 @@ abstract public class Node
 	 */
 	class EventContentFilter extends FlexibleStanzaTypeFilter<Message>
 	{
-		private String firstElement;
-		private String secondElement;
+        private final String firstElement;
+        private final String secondElement;
 
 		EventContentFilter(String elementName)
 		{
-			firstElement = elementName;
+            this(elementName, null);
 		}
 
 		EventContentFilter(String firstLevelEelement, String secondLevelElement)