feat: add Department enum with fields, constructor, and accessor methods

WHAT was implemented:
- Defined an enum `Department` with constants: CS, IT, ECE, CIVIL.
- Each enum constant stores two properties:
  - `head` → name of the department head.
  - `location` → physical location (block name).
- Added a private constructor to initialize enum-specific fields.
- Added getter methods (`getHeadName()`, `getLocation()`) to safely access properties.
- In `EnumDemo1.main()`, demonstrated usage by printing details of `Department.CIVIL`.

WHY this is important:
- Shows that enums in Java are more powerful than simple constants.
- Enums can encapsulate data and behavior, similar to classes.
- Makes enums highly useful for modeling domain-specific constants with metadata.

KEY CONCEPTS COVERED:
1. **Enum with Fields**
   - Unlike plain enums, each constant can hold custom data.
   Example: `CS("John", "Block A")`.

2. **Enum Constructor**
   - Private by default, ensures no external instantiation.
   - Automatically called once per constant.

3. **Methods inside Enum**
   - Getters allow controlled access to internal fields.
   - Enums can also define custom behavior per constant if needed.

4. **Encapsulation in Enums**
   - Enums combine fixed constants with associated attributes.
   - Improves readability and reduces hardcoding in business logic.

REAL-WORLD APPLICATIONS:
- **University/College Systems** → Departments with head and location details.
- **Banking/Finance** → Enum of account types with interest rates and policies.
- **E-commerce** → Enum of order statuses with descriptions and workflows.
- **Transport** → Enum of stations/routes with location metadata.

BEST PRACTICES:
- Keep enum fields `private final` (immutable after initialization).
- Provide getters instead of exposing fields directly.
- Use enums instead of parallel arrays or switch-case chains for related constants.
- Enum names → singular (Department), constants → uppercase (CS, IT, CIVIL).

KEYWORDS:
enum with fields, enum constructor, enum methods, encapsulation, department metadata.

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

Author: Someshdiwan

Section20JAVA.lang.Package/src/EnumDemo1.java

@@ -1,34 +1,31 @@
-//Solve and watch this video Again.
-
-enum Department
-{
-    CS("John","Block A"),IT("Smith","Block B"),CIVIL("Srinivas","Block C"),ECE("Dave","Block D");
+enum Department {
+    CS("John","Block A"),
+    IT("Smith","Block B"),
+    ECE("Dave","Block D"),
+    CIVIL("Srinivas","Block C");
 
     String head;
     String location;
 
-    private Department(String head,String loc)
-    {
+    private Department(String head,String loc) {
         this.head=head;
         this.location=loc;
     }
-    public String getHeadName()
-    {
+
+    public String getHeadName() {
         return head;
     }
-    public String getLocation()
-    {
+
+    public String getLocation() {
         return location;
     }
 }
 
-public class EnumDemo1
-{
-    public static void main(String[] args)
-    {
-        Department d=Department.CS;
+public class EnumDemo1 {
+    public static void main(String[] args) {
+        Department d=Department.CIVIL;
 
         System.out.println(d.getHeadName());
         System.out.println(d.getLocation());
     }
-}
+}