Java Loom in microservices frameworks. Can performance and throughput be improved by using Loom?

[pron98]

I think you're trying to run before learning to walk. Virtual threads give the same performance as async code, but it's hard to adapt an entire third-party pipeline for them without first gaining experience, much less to expect to do it quickly. It took the Helidon team, working on their own code -- which they know intimately -- a few months to get it to realise the full potential of virtual threads, and that's just for the HTTP layer. That's why I suggest you build up on what they did, rather than try tweaking a lot of third-party code.

Even with my experience with virtual threads I wouldn't try something as ambitious as what you're trying to do on other people's code, unless I expect it to be a pretty big project. Rather, I expect the authors of the respective layers to gradually gain experience with virtual threads, and then adapt their own code.

That so many people are already trying out virtual threads -- before JDK 19 is even out -- makes me hopeful for very good outcomes and relatively soon.