feat(LinkedHashMapDemo1): compare ordering behavior of LinkedHashMap vs HashMap

What
- Added LinkedHashMapDemo1 class.
- Inserted the same key-value pairs ("Orange",10), ("Apple",20), ("Guava",13) into both a LinkedHashMap and a HashMap.
- Iterated over each map and printed entries to highlight ordering differences.

Why
- To demonstrate that LinkedHashMap preserves insertion order, while HashMap does not guarantee any order.
- Clarifies a common misconception for beginners that both behave the same.
- Helps developers choose the correct map type when predictable iteration order is required.

How
- Created linkedHashMap and inserted three entries in order.
- Iterated via entrySet() and printed results → preserves insertion sequence.
- Created hashMap with same entries.
- Iterated via entrySet() → order may vary depending on hash distribution.
- Added explanatory comments for clarity.

Logic
- Inputs: three string keys with integer values.
- Processing:
  - LinkedHashMap internally uses a doubly-linked list along with buckets → preserves insertion order.
  - HashMap uses hashing only → iteration order is bucket-dependent, not predictable.
- Outputs:
  - LinkedHashMap → prints exactly in the order of insertion: Orange, Apple, Guava.
  - HashMap → may print in different order, e.g., {Guava, Orange, Apple}.

Real-life applications
- Use LinkedHashMap when insertion order matters (e.g., displaying data in consistent order).
- Use HashMap when only key lookup speed matters and ordering is irrelevant.
- Use LinkedHashMap with accessOrder=true for LRU cache implementations.

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

Author: Someshdiwan

Section 25 Collections Frameworks/Map Interface/Linked HashMap/src/LinkedHashMapDemo1.java

@@ -5,6 +5,7 @@
 public class LinkedHashMapDemo1 {
     public static void main(String[] args) {
         LinkedHashMap<String, Integer> linkedHashMap = new LinkedHashMap<>();
+
         // But it maintains order.
         linkedHashMap.put("Orange",10);
         linkedHashMap.put("Apple",20);