private void generateConfigNode(PrintWriter xml, InnerNode node) throws Exception {
                // print all leaf nodes as config values
                Field[] fields = node.getClass().getDeclaredFields();
                for (Field field : fields) {
                    generateConfigField(xml, node, field);
                }
            }
@param config add this config to the application
@return builder
application/src/main/java/com/yahoo/application/Application.java