feat: Add ExampleOverriding to demonstrate method overriding and upcasting

WHAT the code does:
Defines class car with methods:
- start(): prints "Car Started".
- accelerate(): prints "Car is Accelerated".
- changegear(): prints "Manually We Can Change Car Gear".
Defines subclass LuxaryCar extending car:
- Overrides start() to print "Baap Hu Tera".
- Overrides changegear() to print "Automatic Start and Change Gear".
- Adds openRoof(), specific to LuxaryCar.
Defines ExampleOverriding with main():
- Creates a LuxaryCar object stored in a car reference (upcasting).
- Calls start(), accelerate(), and changegear() to demonstrate polymorphism.

WHY this matters:
Demonstrates **method overriding**, where subclass methods replace superclass behavior at runtime.
Shows **upcasting**: a superclass reference can hold a subclass object.
Illustrates polymorphism: overridden methods are resolved by the actual object type (LuxaryCar), not the reference type (car).
Reinforces that subclass-specific methods (like openRoof()) cannot be called on a superclass reference.

HOW it works:
car c = new LuxaryCar();
- c.start() → resolved at runtime → LuxaryCar.start() → prints "Baap Hu Tera".
- c.accelerate() → not overridden → car.accelerate().
- c.changegear() → overridden → LuxaryCar.changegear().
- c.openRoof() → invalid because car reference type does not declare it.

Tips and gotchas:
Class names should follow Java conventions: Car and LuxuryCar instead of car and LuxaryCar.
Upcasting improves flexibility but restricts access to subclass-only features unless downcasting is used.
System.out.println("Baap Hu Tera") is unconventional—consider clearer domain-appropriate messages for professional code.
openRoof() could be accessed if the reference is explicitly cast back to LuxaryCar.

Use-cases:
Educational demonstration of overriding and polymorphism.
Basis for designing extensible systems where subclasses define specific behavior.
Foundation for patterns like dependency injection and runtime behavior customization.

Short key: class-car luxurycar overriding upcasting polymorphism.

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

Author: Someshdiwan

Section12Inheritance/src/ExampleOverriding.java

@@ -1,22 +1,23 @@
-//Car and LuxaryCar
-class car
-{
+class car {
     public void start(){System.out.println("Car Started");}
     public void accelerate(){System.out.println("Car is Accelerated");}
     public void changegear(){System.out.println("Manually We Can Change Car Gear");}
 }
-class LuxaryCar extends car
-{
+
+class LuxaryCar extends car {
     public void start(){System.out.println("Baap Hu Tera");}
     public void changegear(){System.out.println("Automatic Start and Change Gear");}
     public void openRoof(){System.out.println("Sun Roof is open and Fast Speed and fast moving sports car");}
 }
 
-public class ExampleOverriding
-{
-    public static void main(String[] args)
-    {
+public class ExampleOverriding {
+    public static void main(String[] args) {
         car c = new LuxaryCar();
+        /*you can store a subclass object inside a superclass reference.
+        This is called upcasting.
+
+        “c is a reference of type car, but it is pointing to an object of type LuxaryCar.”
+        “Superclass reference, subclass object.”*/
         c.start();
         c.accelerate();
         c.changegear();
@@ -29,6 +30,6 @@ public static void main(String[] args)
 The reference car c = new LuxaryCar(); demonstrates polymorphism. While c is of type car,
 the overridden method in LuxaryCar is executed because the object is of type LuxaryCar.
 
-Downcasting:
+Down casting:
 To access the openRoof() method, you need to downcast c to LuxaryCar using (LuxaryCar) c.
-*/
+*/