private boolean isClassBox(String owner) {

        if (!owner.startsWith("java/lang/")) {
            return false;
        }

        String className = owner.substring("java/lang/".length());

        return (className.equals("Integer") ||
            className.equals("Double") ||
            className.equals("Long") ||
            className.equals("Char") ||
            className.equals("Byte") ||
            className.equals("Boolean")) ||
            className.endsWith("Number");
    }