What You Will Learn

• What is MVC?
• Why MVC is Needed
• MVC Components
• Request Processing Flow
• Java MVC Implementation
• Spring MVC Architecture
• Enterprise Use Cases
• Benefits and Limitations
• Interview Questions

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Introduction

Most enterprise applications need to separate:

User Interface

Business Logic

Data Access Logic

Without proper separation:

public class CustomerPage {

   public void saveCustomer() {

      // UI Logic

      // Business Logic

      // Database Logic

   }
}

Problems:

Huge Classes

Hard Maintenance

Difficult Testing

Poor Scalability

MVC solves this problem.

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What is MVC?

MVC stands for:

M = Model

V = View

C = Controller

MVC separates application responsibilities into independent layers.

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Purpose of MVC

Primary Goal:

Separation Of Concerns

Each layer has a dedicated responsibility.

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MVC Architecture

flowchart LR
    A[User]
    B[Controller]
    C[Model]
    D[View]

    A --> B
    B --> C
    C --> D
    D --> A

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MVC Components

Model

Represents:

Business Logic

Domain Objects

Database Data

Examples:

Customer

Account

Order

Employee

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View

Responsible for:

Displaying Data

User Interface

HTML Pages

React Pages

Angular Pages

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Controller

Acts as:

Request Handler

Traffic Controller

Coordinator

Receives requests and invokes business logic.

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Real World Analogy

Restaurant Example:

Customer = User

Waiter = Controller

Chef = Model

Food = View

Workflow:

Customer Places Order

↓

Waiter Takes Order

↓

Chef Prepares Food

↓

Food Served

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Request Flow

flowchart LR
    A[Browser]
    B[Controller]
    C[Service]
    D[Database]
    E[View]

    A --> B
    B --> C
    C --> D
    D --> C
    C --> B
    B --> E

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MVC Workflow

Step 1

User sends request.

GET /customers

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Step 2

Controller receives request.

@GetMapping("/customers")

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Step 3

Controller calls service layer.

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Step 4

Service fetches data.

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Step 5

Data returned to controller.

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Step 6

Controller returns view.

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Step 7

View displayed to user.

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MVC Example

Customer Management Application.

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Model Class

public class Customer {

    private Long id;

    private String name;

    private String email;

    // Getters Setters
}

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Service Layer

@Service
public class CustomerService {

    public List<Customer> getCustomers() {

        return List.of(
            new Customer(
                1L,
                "John",
                "[email protected]"
            )
        );
    }
}

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Controller

@Controller
public class CustomerController {

    @Autowired
    private CustomerService service;

    @GetMapping("/customers")
    public String customers(
            Model model) {

        model.addAttribute(
                "customers",
                service.getCustomers());

        return "customers";
    }
}

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View (Thymeleaf)

<table>
   <tr th:each="customer : ${customers}">
      <td th:text="${customer.name}"></td>
   </tr>
</table>

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MVC Execution Flow

sequenceDiagram

Browser->>Controller: GET /customers

Controller->>Service: getCustomers()

Service->>Database: Fetch Data

Database-->>Service: Customers

Service-->>Controller: Response

Controller-->>View: Model Data

View-->>Browser: HTML Page

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Spring MVC Architecture

Core Components:

DispatcherServlet

Controller

Service

Repository

View Resolver

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Spring MVC Flow

flowchart LR
    A[Client]
    B[DispatcherServlet]
    C[Controller]
    D[Service]
    E[Repository]
    F[Database]
    G[ViewResolver]

    A --> B
    B --> C
    C --> D
    D --> E
    E --> F
    C --> G

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DispatcherServlet

Heart of Spring MVC.

Responsibilities:

Receive Requests

Find Controller

Execute Controller

Return Response

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Front Controller Pattern

Spring MVC internally uses:

Front Controller Pattern

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Front Controller Flow

flowchart LR
    A[Client Request]
    B[DispatcherServlet]
    C[Controllers]

    A --> B
    B --> C

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Banking Example

Internet Banking Application.

Models:

Account

Transaction

Customer

Controllers:

AccountController

TransactionController

Views:

Account Summary

Transaction History

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Banking MVC Flow

flowchart LR
    A[User]
    B[Account Controller]
    C[Account Service]
    D[Account Repository]
    E[Database]

    A --> B
    B --> C
    C --> D
    D --> E

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Insurance Example

Claim Management System.

Models:

Claim

Policy

Customer

Controllers:

ClaimController

PolicyController

Views:

Claim Dashboard

Policy Details

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Insurance Workflow

flowchart LR
    A[User]
    B[Claim Controller]
    C[Claim Service]
    D[Claim Repository]
    E[Database]

    A --> B
    B --> C
    C --> D
    D --> E

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REST API MVC

Modern Spring Boot applications:

Controller

↓

Service

↓

Repository

Return:

{
  "id": 1,
  "name": "John"
}

Instead of HTML.

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REST MVC Flow

flowchart LR
    A[Client]
    B[RestController]
    C[Service]
    D[Repository]
    E[Database]

    A --> B
    B --> C
    C --> D
    D --> E

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MVC In Spring Boot

Annotations:

@Controller

@RestController

@Service

@Repository

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Enterprise Examples

Banking

Online Banking

Account Management

Transaction History

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Insurance

Policy Management

Claims Processing

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Retail

Order Management

Inventory Tracking

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Healthcare

Patient Management

Appointment Scheduling

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Benefits

✅ Separation Of Concerns

✅ Easier Maintenance

✅ Better Testability

✅ Improved Scalability

✅ Reusable Components

✅ Cleaner Architecture

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Limitations

❌ More Layers

❌ Additional Complexity

❌ Small Applications May Not Need MVC

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When To Use

Use MVC when:

• Building Web Applications
• Building Enterprise Systems
• Multiple Teams Work Together
• Clear Separation Is Needed

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When Not To Use

Avoid when:

• Simple Utility Applications
• Very Small Projects

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MVC vs Layered Architecture

Feature	MVC	Layered
Focus	UI Separation	Business Layer Separation
View Layer	Yes	Optional
Web Applications	Excellent	Good

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MVC vs MVP

Feature	MVC	MVP
Controller	Yes	No
Presenter	No	Yes
Coupling	Moderate	Lower

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MVC vs MVVM

Feature	MVC	MVVM
Controller	Yes	No
ViewModel	No	Yes
Popular In	Spring	Angular, WPF

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Real Enterprise Architecture

flowchart LR
    A[Client]
    B[Controller]
    C[Service]
    D[Repository]
    E[Database]

    A --> B
    B --> C
    C --> D
    D --> E

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Interview Questions

What is MVC?

A software architecture pattern that separates application into Model, View, and Controller.

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What is Model?

Business data and logic.

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What is View?

Presentation layer.

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What is Controller?

Handles requests and coordinates workflow.

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What is DispatcherServlet?

Front Controller in Spring MVC.

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MVC Used In?

Spring MVC

Spring Boot

Struts

JSF

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Main Benefit?

Separation of concerns.

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Key Takeaways

• MVC stands for Model View Controller.
• Separates UI, Business Logic, and Data.
• Improves maintainability and scalability.
• Spring MVC is the most common Java implementation.
• DispatcherServlet acts as Front Controller.
• Widely used in Banking, Insurance, Retail, and Healthcare applications.
• Foundation for modern Spring Boot applications.

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