class Main {
    public static void main(String[] args) {
        String result = "";
        for (Person p: persons) {
            foo();
            result += p.getName() + ",";
            bar();
        }
        for(int i = 0 ; i < persons.size() ; i++) {
            foo();
            result += persons.get(i).getName() + ",";
            bar();
        }
        return result;
    }
}

class Main {
    public static void main(String[] args) {
        StringBuilder result = new StringBuilder();
        for (Person p: persons) {
            result.append(p.getName() + ",");
        }
        return result.toString();
    }
}