What is the out put of this code? In the description

Question

ArrayList<Long> table = new ArrayList<>();
int position = 1;
table.add(10);
table.add(5);
table.add(position, 15);
table.remove(2);
for (Integer i: table){
    sum += i;
}
System.out.println(sum);

Confused by this but it was on a test and not explained

Answer 1

the output should be 25.
don't forget that indexes start from zero.

10 is added to the first index 0
5 is added to the second index 1
then 15 is added to position = 1 and that replaces 5. so the list now has {10,15}
then remove the 2 index, it doesn't exit only index 0 = 10 and index 1 = 15 exit, so nothing happens.
in the for loop all the elements are summed so 10 + 15 = 25

Answer 2

here's the correct code by the way :
import java.util.*;
public class Program
{
public static void main(String[] args) {
int sum =0;
ArrayList<Integer> table = new ArrayList<>();
int position = 1;
table.add(10);
table.add(5);
table.add(position, 15);
table.remove(2);
for (Integer i: table){
sum += i;
}
System.out.println(sum);

}
}