diff --git a/source/java/org/alfresco/opencmis/mapping/ContentStreamLengthProperty.java b/source/java/org/alfresco/opencmis/mapping/ContentStreamLengthProperty.java
index 1fe3257dc7..70c4f9630f 100644
--- a/source/java/org/alfresco/opencmis/mapping/ContentStreamLengthProperty.java
+++ b/source/java/org/alfresco/opencmis/mapping/ContentStreamLengthProperty.java
@@ -53,7 +53,7 @@ public class ContentStreamLengthProperty extends AbstractProperty
         {
             return contentData.getSize();
         }
-        return 0L;
+        return null;
     }
 
     public QName getMappedProperty()
diff --git a/source/java/org/alfresco/opencmis/mapping/ContentStreamMimetypeProperty.java b/source/java/org/alfresco/opencmis/mapping/ContentStreamMimetypeProperty.java
index efee98e777..1d916ab88c 100644
--- a/source/java/org/alfresco/opencmis/mapping/ContentStreamMimetypeProperty.java
+++ b/source/java/org/alfresco/opencmis/mapping/ContentStreamMimetypeProperty.java
@@ -56,7 +56,7 @@ public class ContentStreamMimetypeProperty extends AbstractProperty
         {
             return contentData.getMimetype();
         }
-        return "";
+        return null;
     }
 
     public String getLuceneFieldName()