Sort ArrayList reverse without implementing any method by user?

Question

   import java.util.*;
    public class Details  {

        public static void main(String args[]){
           ArrayList<String> arraylist = new ArrayList<String>();
           arraylist.add("AA");
           arraylist.add("ZZ");
           arraylist.add("CC");
           arraylist.add("FF");


           System.out.println("Before Sorting:");
           for(String str: arraylist){
                System.out.println(str);
            }

           /* Sorting in decreasing order*/

        }
    }

Now how would I do this? Im new in this field. If this stupid then I would delete it but please help me I really need this to be answered.

Answer 1

As of Java 8, List has a sort method that takes a Comparator parameter. The natural ordering for a list of strings is alphabetic order. To sort the items of a list in their natural order you can use Comparator.naturalOrder() as the Comparator. To sort the items of a list in the reverse of their natural order, you can use Comparator.reverseOrder().

List<String> list = Arrays.asList("AA", "ZZ", "CC", "FF");
list.sort(Comparator.reverseOrder());
System.out.println(list);

If you are on an older version of Java, though I don't see a good reason for that, then you could use Collections.sort with Collections.reverseOrder() instead:

List<String> list = Arrays.asList("AA", "ZZ", "CC", "FF");
Collections.sort(list, Collections.reverseOrder());
System.out.println(list);