// debug purposes: to inspect unknown objects at runtime
static void inspect(Object obj) {
    try {
        for (Field f : obj.getClass().getDeclaredFields()) {
            f.setAccessible(true);
            System.out.printf("%s %s %s %s%n",
                    Modifier.toString(f.getModifiers()),
                    f.getType().getSimpleName(),
                    f.getName(),
                    f.get(obj)
            );
            if ("Object[]".equals(f.getType().getSimpleName())) {
                LOG.warn("further inspect object " + f.get(obj));
            }
            if ("int".equals(f.getType().getSimpleName())) {
                LOG.warn("expected size " + f.get(obj));
            }
            if ("List".equals(f.getType().getSimpleName())) {
                List<Object> objects = (List<Object>)(List<?>) f.get(obj);
                for (Object o : objects) {
                    inspect(o);
                }
            }
        }
    } catch (IllegalAccessException iae) {
        System.out.println("IllegalAccessException : " + iae.getMessage());
    }
}