Do you have a requirement to sort the list? Or just to get the smallest value?

If all you want is the smallest value, there's no need to sort.

If you want to sort, then java.util.Collections has a sort() method that takes a List parameter, or, if you need to write your own, google for sorting algorithms or check your textbook.

Once you've clarified your actual requirements and taken your best shot, post again, showing your efforts and asking a more specific question than, "How do I sort?"