🛡️ Online Complaint Management System — Java

A Secure, Role-Based and SLA-Aware Complaint Lifecycle Management System Built with Core Java

A complete console-based complaint management solution featuring secure authentication, role-based access control, persistent storage, controlled complaint workflows, SLA tracking, automatic escalation, audit logging, analytics, feedback management, and automated testing.

Features • Architecture • Installation • Usage • Testing • Documentation

📌 Project Overview

The Online Complaint Management System is an industry-oriented Core Java application designed to manage the complete lifecycle of complaints in a secure, structured, and transparent manner.

The system provides separate User and Administrator roles.

Users can register securely, log in, submit complaints, receive unique complaint IDs, track complaint progress, view status history, and provide feedback after resolution.

Administrators can manage complaints through assignment, priority updates, status transitions, resolution handling, filtering, SLA monitoring, escalation, closure, and analytics.

Unlike a basic CRUD application, this project focuses on real-world software engineering concepts including:

Layered architecture
Secure password management
Authentication and authorization
Business workflow validation
Persistent application data
SLA-based complaint monitoring
Auditability and status history
Automated unit testing

✨ Key Features

👤 User Management

Secure user registration
User authentication
Unique user ID generation
Password hashing using PBKDF2
Random password salts
Role-Based Access Control
Complaint ownership validation

📝 Complaint Management

Submit new complaints
Automatic unique complaint ID generation
Multiple complaint categories
Priority-based classification
Track complaint status
View personal complaints
View complete complaint history
Persistent complaint storage

🛠️ Administrator Management

View all complaints
Search complaints by ID
Assign complaints
Update complaint status
Change complaint priority
Add resolution details
Filter complaints
Close resolved complaints
View complaint analytics

⏱️ SLA Management

The system automatically associates an SLA target with each priority.

Priority	SLA Target
🔵 LOW	72 Hours
🟢 MEDIUM	48 Hours
🟠 HIGH	24 Hours
🔴 CRITICAL	4 Hours

The system can identify complaints that are:

Within SLA
Near deadline
SLA breached
Escalated

🔐 Security

PBKDF2 with HMAC-SHA256 password hashing
Random cryptographic salts
No plain-text password storage
Role-based authorization
Complaint ownership protection
Input validation
Controlled complaint state transitions

📊 Additional Features

Complaint status history
User feedback and ratings
Administrative analytics
Automatic escalation support
Audit logging
Persistent file-based storage
Custom exception handling
JUnit 5 automated tests

🔄 Complaint Lifecycle

The primary complaint workflow follows:

┌──────────┐
│   OPEN   │
└────┬─────┘
     │
     ▼
┌────────────┐
│  ASSIGNED  │
└─────┬──────┘
      │
      ▼
┌────────────────┐
│  IN_PROGRESS   │
└───────┬────────┘
        │
        ▼
┌────────────┐
│  RESOLVED  │
└─────┬──────┘
      │
      ▼
┌──────────┐
│  CLOSED  │
└──────────┘

The system also supports controlled alternative transitions such as reopening a resolved complaint when additional work is required.

Invalid transitions are blocked through business rules and custom exception handling.

🏗️ System Architecture

The project follows a layered architecture:

┌─────────────────────────────────────────┐
│              USER / ADMIN               │
└────────────────────┬────────────────────┘
                     │
                     ▼
┌─────────────────────────────────────────┐
│            PRESENTATION LAYER           │
│                 Main.java               │
│        Menus • Input • Output           │
└────────────────────┬────────────────────┘
                     │
                     ▼
┌─────────────────────────────────────────┐
│              SERVICE LAYER              │
│                                         │
│     UserService • ComplaintService      │
│                                         │
│ Authentication • Authorization          │
│ Workflow • SLA • Analytics              │
└────────────────────┬────────────────────┘
                     │
                     ▼
┌─────────────────────────────────────────┐
│             REPOSITORY LAYER            │
│                                         │
│            FileRepository<T>            │
└────────────────────┬────────────────────┘
                     │
                     ▼
┌─────────────────────────────────────────┐
│                DATA LAYER               │
│                                         │
│       users.dat • complaints.dat        │
└─────────────────────────────────────────┘

This architecture provides:

Separation of concerns
Better maintainability
Improved testability
Reusable components
Easier database migration
Future REST API integration support

📂 Project Structure

Online-Complaint-Management-System-Java/
│
├── src/
│   ├── main/
│   │   └── java/
│   │       └── com/
│   │           └── complaintmanagement/
│   │               │
│   │               ├── enums/
│   │               ├── exception/
│   │               ├── model/
│   │               ├── repository/
│   │               ├── service/
│   │               ├── utility/
│   │               └── Main.java
│   │
│   └── test/
│       └── java/
│           └── com/
│               └── complaintmanagement/
│                   └── ComplaintServiceTest.java
│
├── data/
├── docs/
│   ├── ARCHITECTURE.md
│   ├── PROJECT_DOCUMENTATION.md
│   ├── TESTING.md
│   └── USER_GUIDE.md
│
├── logs/
├── outputs/
├── screenshots/
│   ├── user-registration.png
│   ├── user-login-dashboard.png
│   ├── complaint-submitted.png
│   ├── complaint-tracking.png
│   ├── admin-dashboard.png
│   ├── complaint-assigned.png
│   ├── complaint-in-progress.png
│   ├── complaint-resolved.png
│   ├── complaint-history.png
│   ├── feedback-submitted.png
│   ├── complaint-closed.png
│   └── analytics-dashboard.png
│
├── .gitignore
├── pom.xml
└── README.md

🧰 Technology Stack

Technology	Usage
Java	Core application development
OOP	Modular application design
Java Collections	In-memory data management
Java Streams	Filtering and analytics
Java Serialization	Persistent file storage
PBKDF2	Secure password hashing
JUnit 5	Automated unit testing
Apache Maven	Build and dependency management
Git	Version control
GitHub	Source-code hosting and project portfolio
VS Code	Development environment

🧠 Core Concepts Demonstrated

This project demonstrates practical implementation of:

Object-Oriented Programming
Encapsulation and abstraction
Layered software architecture
Java Collections Framework
Java Stream API
Generic programming
Java Serialization
File handling
Authentication and authorization
Password hashing and salting
Role-Based Access Control
Input validation
Custom exception handling
State transition management
SLA monitoring
Audit logging
Unit testing
Maven project management

🚀 Installation & Setup

Prerequisites

Ensure the following are installed:

Java JDK 17 or later
Apache Maven
Git
VS Code with Extension Pack for Java

Verify the installations:

java --version
javac --version
mvn --version
git --version

1. Clone the Repository

git clone https://github.com/Vayu-143/Online-Complaint-Management-System-Java.git

Navigate to the project:

cd Online-Complaint-Management-System-Java

2. Compile the Project

mvn clean compile

3. Run Automated Tests

mvn test

4. Start the Application

mvn exec:java

💻 Application Workflow

User Workflow

Register Account
      ↓
Secure Login
      ↓
Submit Complaint
      ↓
Receive Unique Complaint ID
      ↓
Track Complaint
      ↓
View Status History
      ↓
View Resolution
      ↓
Submit Feedback

Administrator Workflow

Admin Login
     ↓
View/Search Complaints
     ↓
Assign Complaint
     ↓
Update to IN_PROGRESS
     ↓
Add Resolution
     ↓
Mark as RESOLVED
     ↓
User Provides Feedback
     ↓
Close Complaint
     ↓
View Analytics

🖥️ Application Screenshots

User Registration

User Dashboard

Complaint Submission

Complaint Tracking

Administrator Dashboard

Complaint Assignment

Complaint In Progress

Complaint Resolution

Complaint History

User Feedback

Complaint Closure

Analytics Dashboard

🧪 Testing

The project uses JUnit 5 for automated testing.

Run:

mvn clean test

Current test result:

Tests run: 5
Failures: 0
Errors: 0
Skipped: 0

BUILD SUCCESS

Tested Components

Password validation
Feedback rating validation
Default complaint status
Critical-priority SLA configuration
Automatic complaint history creation

Additional manual testing covers:

User registration
Duplicate account prevention
Authentication
Complaint submission
Complaint ownership
Administrator operations
Status transitions
Resolution workflow
Feedback submission
Complaint closure
Persistent storage

💾 Data Persistence

Application data is stored locally using Java object serialization.

data/
├── users.dat
└── complaints.dat

The repository layer is designed separately from the business logic, making future migration to technologies such as JDBC, MySQL, PostgreSQL, or Spring Data JPA easier.

Runtime .dat files are excluded from version control to prevent local user and complaint records from being committed to the repository.

🔒 Security Design

Password Protection

User Password
      │
      ▼
Random Salt Generation
      │
      ▼
PBKDF2WithHmacSHA256
      │
      ▼
Derived Password Hash
      │
      ▼
Store Hash + Salt

Passwords are never intentionally stored as plain text.

Access Control

Authenticated Account
        │
        ▼
     Role Check
     /        \
   USER      ADMIN
    │          │
    ▼          ▼
Personal     System-Wide
Complaints   Management

📈 Analytics

The administrator analytics module provides information such as:

Total number of complaints
Complaint count by status
Critical complaint count
Escalated complaint count
User feedback statistics
Average complaint rating

This demonstrates how operational complaint data can be transformed into useful management insights.

📚 Documentation

Detailed project documentation is available inside the docs/ directory:

Document	Description
`PROJECT_DOCUMENTATION.md`	Complete project explanation and technical overview
`ARCHITECTURE.md`	System architecture, package structure, and data flow
`TESTING.md`	Automated and manual testing strategy
`USER_GUIDE.md`	Installation and complete application usage guide

⚠️ Current Limitations

The current version is designed as a Core Java portfolio and learning project.

Current limitations include:

Console-based interface
Local file-based persistence
Single-machine execution
No external relational database
No real-time email or SMS notifications
No web-based frontend

These limitations provide clear opportunities for future development.

🔮 Future Enhancements

Planned and possible improvements include:

🎯 Learning Outcomes

Through this project, I strengthened my understanding of:

Building structured applications with Core Java
Designing maintainable layered architectures
Implementing real-world business workflows
Applying OOP concepts in practical applications
Designing secure authentication mechanisms
Implementing role-based authorization
Managing persistent application data
Designing controlled state transitions
Implementing SLA-based business rules
Writing automated tests using JUnit
Managing Java projects using Maven
Using Git and GitHub for version control

👨‍💻 About the Developer

Vayunandan Mishra

Electronics and Communication Engineering (ECE) student with an interest in Java development, software engineering, IoT, embedded systems, AI, and emerging technologies.

I enjoy building practical, industry-oriented projects that strengthen my understanding of programming, system design, problem-solving, and real-world technology applications.

This project was developed as part of my continuous learning journey and portfolio development.

🤝 Contributions

Contributions, suggestions, and improvements are welcome.

If you would like to contribute:

Fork the repository.
Create a new feature branch.
Make your changes.
Commit your improvements.
Push the branch.
Open a Pull Request.

⭐ Support

If you find this project useful or interesting, consider giving the repository a ⭐ Star.

Your support encourages continued learning and development of more practical engineering and software projects.

Built with ☕ Java and a focus on practical software engineering

Developed by Vayunandan Mishra

ECE Student | Java • Software Development • IoT • Embedded Systems • AI

⭐ Star this repository if you found it useful! ⭐

Name		Name	Last commit message	Last commit date
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data		data
docs		docs
screenshots		screenshots
src		src
.gitignore		.gitignore
README.md		README.md
pom.xml		pom.xml

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