This repository will eventually contain multiple solutions for the same problem. The important thing to keep in mind is that all components need to be possibly scaled up. This means different simultaneous calls might hit different applications, which might in turn hit different middleware.
A fictional Java User Group want to create a platform for their members. If they register they get a certain about of credits (50), and with that they can oder stickers (30). It must be impossible for someone just registered to order multiple sheets of stickers. Please note this is highly simplified. The email is never checked, it doesn't need to be unique, and there is almost no other validation than a check for the current credits of a member.
All solutions will likely be build using Spring Boot 3 for the application. In most cases the middleware can be started by using docker, from the docker file in the solution, like here. As Sping Boot requires Java 17, that is needed to run the application.
Graphql is used for the API. As this is also common, you can go to graphiql, if it's
enabled by the spring.graphql.graphiql.enabled property. You can find the schema
used here.