WIP: [AMQ-9394] Tech Preview: Virtual Thread support

[mattrpav]

TODO:

• Throw exception if virtualThreadTaskRunner is enabled and JDK 21 (or higher) is not available
• Breakout the Virtual Thread factory init so it only logs on JDK 17
• Add webpage with instructions and implementation progress status (https://activemq.apache.org/virtual-threads)
• Add a VirtualThreadTaskRunner
• Consider separate config flag for persistenceAdapter TaskRunner
• Replace Thread.yield() usage with VirtualThread friendly alternative

[PascalSchumacher]

Great to see work done on this! 👍

What about other threads like ActiveMQ Data File Writer, ActiveMQ Journal *, can/should these be virtual too or is that a bad idea?

[mattrpav]

Great to see work done on this! 👍

What about other threads like ActiveMQ Data File Writer, ActiveMQ Journal *, can/should these be virtual too or is that a bad idea?

Those are single threaded processing right now. They would most benefit from being converted (or create a configurable alternative) to use Linux's IO_uring (aka kqueue in macOS) vs Virtual Thread (which would block on I/O anyway).

[mattrpav]

Newer PR here: #1172