GenieAshwani/Spark3.0 — reverse-engineered prompt

Build me a Java and Spring demo workspace that feels like a small training project I can run locally and learn from. I want several simple apps included, like a movie booking flow, a car garage billing flow, an ecommerce screen, a train screen, a greeting and welcome API, and a payment gateway with a basic UI.

Please make it easy to start everything, with clear steps in the project for running the server side apps and any UI parts. The apps don’t need to be production grade, but they should actually work end to end with simple sample data, clean screens, and easy to understand code. Include examples for core Java topics too, like collections, exceptions, JDBC, JPA mapping, Spring core, and multithreading, so this can be used as a learning repo.

If anything is missing or unclear, make a sensible simple version. Look up current docs online if you need to.