As a Backend developer I want to enable Java 21 Virtual Threads instead of using Thread Pools

[sekasx]

New Major Version

This is a breaking change. Since this is still in beta, only the minor version will be updated though. TBD the exact versioning

Description

Threads Pools is a major Java new feature, introduced as experimental in Java 19 and maid final in Java 21 which is the next LTS Java Version.

Virtual Threads have significant benefits over Classic Threads:

• https://foojay.io/today/web-crawling-in-java-a-tale-of-classical-threads-and-virtual-threads/
• https://medium.com/@RamLakshmanan/java-virtual-threads-easy-introduction-44d96b8270f8
• https://blog.rockthejvm.com/ultimate-guide-to-java-virtual-threads/

In this ticket Spring needs to be upgrade in Java 21 and the asyncDiscordExecutor needs to be updated to use Virtual Threads. https://www.baeldung.com/spring-6-virtual-threads

Tasks

• [ ] Update/Test the Spring core with Java 21
• [ ] Update Test @Async execution with Virtual Threads
• [ ] Update CI to build the app in Java 21
• [ ] Update AWS environments
• [ ]

[sekasx]

@myrtp please check this