Comment by Two4

Non-MicroProfile Helidon uses a reactive interface for most things, which lends itself well to async operations. It a very nice, simple and powerful abstraction that makes async relatively easy. IMO anything webserver or client should be async when virtual threads aren't available, due to Java having the tendency to quickly build up a ton of threads when you use the one-thread-per-request model. That being said, virtual threads does make that model viable at scale, so reactive async probably isn't as necessary.