import java.util.ArrayList;
import java.util.ListIterator;

public class Main {


    public static void main(String[] args) {
        ArrayList days = new ArrayList<>();

        days.add("Sun");
        days.add("Mon");
        days.add("Tue");
        days.add("Thu");
        days.add("Fri");
        days.add("Sat");

        ListIterator iterator = days.listIterator();

        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }

        iterator.set("None");

        System.out.println("After set : ");

        for (String item : days) {
            System.out.println(item);
        }
    }

}