Parsing grants

src/engine/objects/ItemTemplate.java

@@ -279,6 +279,8 @@ public class ItemTemplate {
                 }
 
             JSONArray powerGrants = (JSONArray) jsonObject.get("item_power_grant");
+
+            if (powerGrants.isEmpty() == false)
                 for (Object o : powerGrants) {
                     JSONObject powerGrantEntry = (JSONObject) o;
                     String power_type = (String) powerGrantEntry.get("power_type");