feat(LambdaExpressionDemo): add demo of sorting collections using lambdas

What
- Added LambdaExpressionDemo class.
- Created a List<Integer> with values [2, 3, 1].
- Sorted integers in descending order using a lambda comparator (b - a).
- Created a List<String> with values ["banana", "apple", "date"].
- Sorted strings by length using a lambda comparator (a.length() - b.length()).
- Printed sorted results.

Why
- Demonstrates how to use lambda expressions to define custom comparators inline.
- Replaces verbose anonymous classes with concise, readable lambdas.
- Shows sorting of both numeric and string data with different criteria.

How
- list.sort((a, b) -> b - a):
  - Subtracts a from b to achieve descending order.
- words.sort((a, b) -> a.length() - b.length()):
  - Compares based on string length, resulting in ascending order by length.
- Print the lists after sorting to verify order.

Logic
- Inputs:
  - list = [2, 3, 1].
  - words = ["banana", "apple", "date"].
- Outputs:
  - Integers sorted descending → [3, 2, 1].
  - Strings sorted by length ascending → ["date", "apple", "banana"].
- Flow:
  1. Populate lists.
  2. Apply sort() with lambdas.
  3. Print sorted collections.
- Edge cases:
  - If comparator returns 0, elements considered equal (order may remain stable).
  - If lists are empty, sort() is a no-op.
- Complexity: O(n log n) sorting.
- Concurrency: Not thread-safe while sorting shared mutable lists.
- Error handling: Not needed here.

Real-life applications
- Sorting employees by salary, then by name.
- Sorting files by size or timestamp.
- Sorting strings by custom metrics (length, frequency of characters, etc.).
- Inline comparators reduce boilerplate in such tasks.

Notes
- Lambdas improve readability compared to explicit Comparator classes.
- For clarity, use Comparator.comparing(...) when criteria are more complex.
- Arithmetic-based comparator (b - a) works for small integers but may overflow; safer is Integer.compare(b, a).

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

Author: Someshdiwan

Section25CollectionFramework/src/ListDemo/ArrayListLinkedListStack/ListEDSortUsingLamda.java renamed to Section 25 Collections Frameworks/List Interface/ArrayList/Lamda Expression/src/LambdaExpressionDemo.java

@@ -1,10 +1,8 @@
-package ListDemo.ArrayListLinkedListStack;
-
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-public class ListEDSortUsingLamda  {
+public class LambdaExpressionDemo  {
     public static void main(String[] args) {
         List<Integer> list = new ArrayList<>();
         list.add(2);
@@ -18,4 +16,4 @@ public static void main(String[] args) {
         words.sort((a,b)->a.length()-b.length());
         System.out.println("Sorted strings by length: " + words);
     }
-}
+}