diff --git a/src/helma/scripting/rhino/MapWrapper.java b/src/helma/scripting/rhino/MapWrapper.java
index ad9d9573..4a4fcc2b 100644
--- a/src/helma/scripting/rhino/MapWrapper.java
+++ b/src/helma/scripting/rhino/MapWrapper.java
@@ -197,7 +197,7 @@ public class MapWrapper extends ScriptableObject {
     }
 
     public Object getDefaultValue(Class hint) {
-        if (hint == String.class) {
+        if (hint == null || hint == String.class) {
             return map == null ? "{}" : map.toString();
         }
         return super.getDefaultValue(hint);