--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/datacage/templating/DefaultVegetationZoneXPathFunction.java	Wed Sep 26 15:48:05 2018 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/datacage/templating/DefaultVegetationZoneXPathFunction.java	Thu Sep 27 18:06:26 2018 +0200
@@ -47,6 +47,10 @@
         if (river == null)
             return null;
 
-        return VegetationZoneServerClientXChange.parseListToDataString(VegetationZoneServerClientXChange.getStandardList(river, this.context));
+        final String value = VegetationZoneServerClientXChange.parseListToDataString(VegetationZoneServerClientXChange.getStandardList(river, this.context));
+        if (value == null)
+            return null;
+
+        return value;
     }
 }
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