allow null for convenience
diff --git a/bundles/org.eclipse.wst.xml.core/src-contentmodel/org/eclipse/wst/xml/core/internal/contentmodel/basic/CMNamedNodeMapImpl.java b/bundles/org.eclipse.wst.xml.core/src-contentmodel/org/eclipse/wst/xml/core/internal/contentmodel/basic/CMNamedNodeMapImpl.java
index 5601956..fee63d2 100644
--- a/bundles/org.eclipse.wst.xml.core/src-contentmodel/org/eclipse/wst/xml/core/internal/contentmodel/basic/CMNamedNodeMapImpl.java
+++ b/bundles/org.eclipse.wst.xml.core/src-contentmodel/org/eclipse/wst/xml/core/internal/contentmodel/basic/CMNamedNodeMapImpl.java
@@ -35,12 +35,14 @@
   }
 
   public CMNamedNodeMapImpl(CMNamedNodeMap initialContentsMap) {
-	  super();
-		int length = initialContentsMap.getLength();
-		for (int j = 0; j < length; j++) {
-			put(initialContentsMap.item(j));
+		super();
+		if (initialContentsMap != null) {
+			int length = initialContentsMap.getLength();
+			for (int j = 0; j < length; j++) {
+				put(initialContentsMap.item(j));
+			}
 		}
-  }
+	}
   /**
    * getLength method
    * @return int