Savindi Ranaweera

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Spring + React Authentication System – Full Details

This is a fully functional Authentication System built using Spring Boot for the backend and ReactJS for the frontend. It features secure user login and registration powered by JWT (JSON Web Tokens), ensuring stateless authentication and protection of sensitive endpoints. New users receive an OTP via email, sent using the JavaMailSender API, to verify their identity before account activation. Additionally, users can reset their passwords via an email link, adding an extra layer of account security.

The system implements robust role-based access control, distinguishing between Admin and User roles. Admin users have access to privileged operations, while standard users are limited to general functionality. On the frontend, React manages protected routes, ensuring that only authenticated users can access restricted pages. The application is styled with Bootstrap 5 for a modern and responsive user experience.

Available API Endpoints:
/register, /verify-otp, /login, /reset-password, /update-password

Tech Stack:
Spring Boot, Spring Security, JavaMailSender, JWT, ReactJS, Bootstrap 5, MySQL

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Access Hub – Group Project (Real-Time Video/Audio Calling)

Access Hub is a real-time communication application built as a collaborative group project. Inspired by platforms like WhatsApp and Google Meet, this app supports one-on-one audio and video calling functionality using JavaFX and a socket-based client-server architecture.

The project was structured into three modular components:

• Shared Module: Contains common utilities, data transfer objects (DTOs), and protocols used across the client and server.
• Client Module: Handles GUI, media capture (video/audio), user interactions, and sending/receiving data streams.
• Server Module: Manages client connections, facilitates signaling, and relays streams between matched peers.

My Key Contribution:
I implemented the core logic that enables real-time bi-directional video and audio communication between two users during a call.

• Designed and coded the media transmission logic to send/receive live video frames and audio chunks between client and server.
• Used JavaFX to access webcam and microphone input and display remote streams in real time.
• Handled socket streams on ports 9090–9093, separating video/audio input/output across threads for smooth parallel execution.
• Ensured proper synchronization between threads to avoid race conditions during simultaneous stream operations.
• Enabled call controls such as toggling video/audio during the session and displaying connection status dynamically in the UI.

My feature allows both users to:

• Initiate or receive a call request
• Stream live video and audio in both directions
• Toggle media inputs on/off during the call
• Maintain connection stability and stream quality through proper thread management and socket reuse

Challenges Solved:

• Minimized latency in media transfer using multithreaded socket programming
• Handled concurrent access to shared resources without deadlocks
• Achieved responsive UI updates during background media streaming

Key Concepts Demonstrated:

• Real-time media streaming (video/audio)
• Client-server socket communication
• Thread synchronization and multithreading
• JavaFX-based media UI development
• Custom protocol handling for call setup and teardown

Tech Stack:
Java SE, JavaFX, Media Streaming, Multithreading, Socket Programming, Maven

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JavaFX Media Player – Full Details

This is a feature-rich Media Player Application developed using JavaFX for the frontend and FXML for layout and UI management. The application allows users to play both video (.mp4) and audio (.mp3) files with smooth playback and interactive controls.

Key Functionalities:
- Uses JavaFX MediaPlayer and MediaView for media playback.
- Users can play and pause media with dedicated buttons.
- Includes a volume control slider for adjusting audio levels.
- Features a media seek slider allowing users to skip forward or backward through the media.
- The user interface is built using FXML, ensuring a clean and maintainable code structure.

The player offers a minimal and intuitive UI, making it easy for users to interact with media content. The layout is responsive, and playback operations are handled smoothly, demonstrating practical use of JavaFX components for real-world desktop application development.

Key Concepts Demonstrated:

• Media playback using JavaFX's MediaPlayer and MediaView
• Handling multimedia formats (.mp4 and .mp3)
• Interactive controls (play, pause, volume, seek)
• Building UIs with FXML and event-driven programming
• Thread-safe UI updates and responsive behavior

Tech Stack:
JavaFX, FXML, Maven, MediaPlayer, MediaView

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MiniBrowserFX – Full Details

MiniBrowserFX is a minimal custom-built browser using JavaFX designed to help understand the internal mechanics of how a web browser works from scratch. It provides a hands-on implementation of essential browser features, including URL parsing, sending HTTP GET requests manually, handling HTTP responses, and rendering content.

The project includes a clean GUI built with JavaFX components such as TextField, Button, and WebView. The user can enter any URL, and the browser will parse it, validate the format, and send a manual HTTP request using Java sockets (or HttpURLConnection) to fetch the page.

On receiving the HTTP response, the program extracts status codes, headers, and body content to simulate how real browsers handle HTTP protocol. Simple HTML content is rendered in a WebView, making it readable and visually displayed.

Tech Stack: Java, JavaFX, HTTP, Networking, Java Sockets

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MiniServer – Full Details

The MiniServer is a simple HTTP web server built entirely in Java to simulate the fundamentals of how a real-world server processes client requests and serves responses. This project allowed me to go beyond the abstraction of frameworks and explore low-level server operations directly through socket programming and stream handling.

By building MiniServer, I not only solidified my understanding of network programming and I/O in Java but also learned how web browsers and servers communicate over HTTP. It was a great learning experience in implementing the fundamentals from scratch.

Tech Stack: Java, Socket Programming

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To-Do List App – Full Details

The To-Do List App is a fully functional task management application that allows users to add, edit, delete, and mark tasks as completed. Built using modern tools like Vite and Firebase Firestore, the app provides a smooth and interactive user experience with real-time synchronization of data.

The interface is simple yet effective. It features an input bar where users can type in tasks and either hit enter or click a button to add them. Users can edit tasks in-line and remove them with a click. Each task also has a checkbox to mark it as completed. Tasks are stored in Firebase Firestore, ensuring data persists even if the page is refreshed.

One of the key highlights of this app is its real-time data sync. As soon as a task is added or updated, the change is reflected instantly thanks to Firebase’s real-time database capabilities. Additionally, Firebase Hosting was used to deploy the app online, making it accessible and shareable with others.

The frontend was built using Vite for fast bundling and development, along with jQuery for DOM manipulation. HTML and CSS were used for the structure and styling, with a focus on creating a clean and responsive layout.

Tech Stack: Vite, jQuery, HTML, CSS, Firebase Firestore, Firebase Hosting

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Google Homepage Clone – Full Details

The Google Homepage Clone is a frontend project that meticulously replicates the design and layout of the original Google homepage. Developed using only HTML and CSS, this project serves as a practical exercise in web design, focusing on structure, styling, and responsiveness without incorporating any JavaScript functionality.

The project features a centered Google logo, a styled search input field, and two interactive buttons: "Google Search" and "I'm Feeling Lucky." Additionally, it includes a navigation bar with links such as Gmail and Images, as well as a footer containing various informational links, mirroring the authentic Google homepage layout.

In constructing this clone, I emphasized semantic HTML to ensure proper document structure and accessibility. CSS was utilized to achieve precise positioning, spacing, and styling, including the use of Flexbox for layout alignment and media queries for responsiveness across different screen sizes.

This project not only demonstrates my attention to detail and commitment to replicating complex designs but also reinforces my proficiency in HTML and CSS. It stands as a testament to my dedication to mastering frontend development fundamentals and my ability to translate real-world designs into functional web pages.

Tech Stack: HTML, CSS

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Java Inter-thread Communication – Full Details

This project is designed to illustrate the core principles of **inter-thread communication** in Java. It features a simple producer-consumer model where two threads share a single resource (like a buffer or message), and use synchronization techniques to ensure orderly execution.

- The Producer thread creates data and notifies the Consumer when it's available.
- The Consumer waits until data is available and processes it once notified.
- Both threads share a common object and coordinate using wait() and notify() methods inside synchronized blocks.

This prevents race conditions and avoids busy-waiting by blocking the thread execution until it's safe to proceed.

The project is useful for understanding real-world problems in concurrent systems such as message passing, buffer management, and task scheduling. It reflects how OS-level threads and processes interact using shared memory and signaling mechanisms.

Key Concepts Demonstrated:

• Thread lifecycle and coordination
• Synchronization using intrinsic locks (monitors)
• wait(), notify(), and notifyAll()
• Thread-safe communication
• Practical Producer-Consumer model implementation

Tech Stack:
Java SE, Multithreading, Synchronization, Object Monitor

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