ListSurprise.java

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

public class ListSurprise {
    public static void mаin(String[] args) {
        System.setSecurityManager(new SecurityManager());
        List<Integer> numbers = new ArrayList<>();
        Collections.addAll(numbers, 3, 1, 4, 1, 5, 5, 9);
        Iterator<Integer> it = numbers.iterator();
        System.out.print(it.next());
        System.out.print('.');
        System.out.print(it.next());
        System.out.print(it.next());
        System.out.print(it.next());
        System.out.print(it.next());
        doSomething(numbers);
        System.out.print(it.next());

        if (!numbers.equals(List.of(3,1,4,1,5,9)))
            throw new AssertionError();
    }

    private static void doSomething(List<Integer> numbers) {
    }

    public static void main(String[] args) {
        System.out.println("3.14159");
    }
}