URL Shortener Coding Task

Task

Build a simple URL shortener in a ** preferably JVM-based language** (e.g. Java, Kotlin).

It should:

Accept a full URL and return a shortened URL.
Persist the shortened URLs across restarts.
Allow a user to customise the shortened URL (e.g. user provides my-custom-alias instead of a random string).
Expose a simple UI (basic form is fine — no need for a polished design).
Expose a RESTful API to perform create/read/delete operations on URLs.
→ Refer to the provided openapi.yaml for API structure and expected behaviour.
Include the ability to delete a shortened URL via the API.
Have tests.
Be containerised (e.g. Docker).
Include instructions for running locally.

Fork the repository and work in your fork. Do not push directly to the main repository.
We suggest spending no longer than 4 hours, but you can take longer if needed.
Commit often with meaningful messages.
Write tests.
Use the provided openapi.yaml as a reference.
Focus on clean, maintainable code.

Working code.
Simple UI.
RESTful API matching the OpenAPI spec.
Tests.
Dockerfile.
README with:
- How to build and run locally.
- Example usage (UI and/or API).
- Any notes or assumptions.