feat(ListDemo): add demo of sorting lists with Collections.sort and List.sort

What
- Added ListDemo class.
- Created a List<Integer> with values [1,3,2].
- Demonstrated sorting with list.sort(null), which uses natural ordering (ascending).
- Created a List<String> with values ["banana","apple","date"].
- Sorted words with list.sort(null) (alphabetical order).
- Printed sorted results.

Why
- Shows two equivalent ways of sorting lists:
  - Collections.sort(list).
  - list.sort(null) (preferred since Java 8).
- Demonstrates natural ordering:
  - For integers → ascending numeric order.
  - For strings → lexicographical order.

How
- list = [1,3,2].
- list.sort(null) → [1,2,3].
- words = ["banana","apple","date"].
- words.sort(null) → ["apple","banana","date"].
- Printed both lists.

Logic
- Inputs: integer and string lists.
- Outputs:
  - Sorted integers ascending.
  - Sorted strings alphabetically.
- Flow:
  1. Initialize lists.
  2. Sort integers with list.sort(null).
  3. Sort strings with list.sort(null).
  4. Print results.
- Edge cases:
  - Passing null to sort() means use natural ordering.
  - For custom order, pass Comparator (e.g., Comparator.reverseOrder()).
- Complexity: O(n log n) sort.
- Concurrency: Not thread-safe if list is modified concurrently.

Real-life applications
- Sorting numerical or textual data for reporting, searching, or UI display.
- Using natural ordering without writing explicit comparators.
- Switching between natural and custom order by replacing null with Comparator.

Notes
- Collections.sort(list) and list.sort(null) are interchangeable; list.sort is more modern and direct.
- Natural ordering is defined by Comparable implementation of list elements.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section25CollectionFramework/src/ListDemo/ArrayListLinkedListStack/ListEDSort.java renamed to Section 25 Collections Frameworks/List Interface/ArrayList/src/ListDemo.java

@@ -1,8 +1,6 @@
-package ListDemo.ArrayListLinkedListStack;
-
 import java.util.*;
 
-public class ListEDSort {
+public class ListDemo {
     public static void main(String[] args) {
         List<Integer> list = new ArrayList<>();
         list.add(1);
@@ -11,12 +9,12 @@ public static void main(String[] args) {
 
         //Collections.sort(list);
 
-        //Other method using comparator
+        //Another method using comparator.
         list.sort(null);
         System.out.println(list);
 
         List<String> words = Arrays.asList("banana","apple","date");
         words.sort(null);
         System.out.println(words);
     }
-}
+}