Hello Java friends,

I am new to joining a site like this so let me get straight to the point. I am trying to make an ArrayList that stores the users input of the ages of their grandchildren. I have this code started but am lost from there as I can not find enough information on the web on how to accomplish this task.

Yes, I am an IT student with Java being my last class till I graduate, but this is not an actual assignment. I need to try to learn this task as i will be using a similar function in my project. The age of the grandchildren is something i made up as I seem to be missing how to store user inputs (specifically <Integers>), then to sum all the inputed ages (for right now I am just trying to show all the inputed ages as an array). I will be grateful for any and all help I receive.

CODE:
package grandchildren;

import java.util.Scanner;
import java.util.ArrayList;

public class GrandChildren
{


public static void main(String[] args)
{
Scanner in = new Scanner(System.in);

//My ArrayList (i am getting an redundant data type here)
ArrayList<Integer> childAge = new ArrayList<Integer>();

//Asks for the ages of the grand children
System.out.println("What are the ages of your grand children? ");
int age = in.nextInt();
if (age > 0)
{
childAge.add(age);
}
else
{
for(int i = 0; i <= childAge.size(); i++)
{
//I am getting an error here
System.out.println(childAge[i]);
}
}
}
}