feat: add Enum example demonstrating toString(), name(), and values()

WHAT was added:
- Created an enum `Size` with constants: SMALL, MEDIUM, LARGE, EXTRALARGE.
- Overrode `toString()` specifically for `SMALL` to print "Pizza is small".
- Demonstrated:
  - `toString()` for custom string output.
  - `name()` to fetch the exact declared identifier.
  - `values().length` to count enum constants.

WHY this matters:
- Enums in Java are type-safe constants, better than using raw `int` or `String` constants.
- Demonstrates the difference between:
  - `toString()` → customizable, can be overridden per constant.
  - `name()` → fixed, always returns the declared constant name.
- `values()` is a handy utility to iterate over all enum constants or count them.

HOW it works:
1. `Size.SMALL.toString()` prints "Pizza is small" (overridden).
2. `Size.MEDIUM.name()` prints "MEDIUM" (exact enum identifier).
3. `Size.values().length` prints `4` (total number of constants).

REAL-LIFE APPLICATIONS:
- Pizza ordering system → `Size.SMALL`, `Size.MEDIUM`, etc.
- Traffic lights → `enum Signal { RED, YELLOW, GREEN }`.
- Payment status → `enum Status { PENDING, SUCCESS, FAILED }`.
- Logging levels → `enum LogLevel { INFO, WARN, ERROR }`.
- Role-based access control → `enum Role { ADMIN, USER, GUEST }`.

COMPARISON:
- `toString()` → can be overridden for user-friendly messages (UI display).
- `name()` → always returns constant’s code representation (useful for debugging, persistence).
- `ordinal()` (not shown here) → gives numeric index (but not recommended for persistence as ordering may change).

KEYWORDS:
enum, toString override, name method, values method, type-safe constants, real-world enum use cases.

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

Author: Someshdiwan

Section20JAVA.lang.Package/src/Enum1.java

@@ -1,19 +1,38 @@
 enum Size
 {
-    SMALL{
-       public String toString()
-        {
-            return "Pizza is small";
-        }
-    }, MEDIUM, LARGE, EXTRALARGE
+    SMALL
+            {
+                public String toString()
+                {
+                    return "Pizza is small";
+                }
+    },
+    MEDIUM, LARGE, EXTRALARGE
 }
+
 public class Enum1 {
-    public static void main(String[] args)
-    {
+    public static void main(String[] args) {
         System.out.println(/*"string value of SMALL is " +*/ Size.SMALL.toString());
         System.out.println("string value of MEDIUM is " + Size.MEDIUM.name());
         System.out.println(Size.values().length);
     }
 }
 
-/* In Java, we can get the string representation of enum constants using the toString() method or the name() method.*/
+/*
+1. toString():
+   - By default -> enum constant ka name return karta hai (jaise name()).
+   - Lekin override kar sakte ho per-constant basis.
+   - Example: SMALL -> "Pizza is small" (custom string).
+
+2. name():
+   - Hamesha constant ka original declared name return karega (SMALL, MEDIUM, ...).
+   - Isko override nahi kar sakte.
+
+3. values():
+   - Enum ke sare constants ek array me return karta hai.
+   - Useful for loops or counting constants.
+
+4. Enum is implicitly final and extends java.lang.Enum.
+
+In Java, we can get the string representation of enum constants using the toString() method or the name() method.
+*/