Have you gotten to use loom/virtual threads? I’ve heard pretty interesting stuff about em, but haven’t really spent the time to get into it yet. It’s pretty exciting and tbh gives me an easy elevator pitch to JVM world for people outside of it

If you have a use-case where you currently allocate ~1K threads mostly waiting on I/O switching to virtual threads is a one-liner ("Thread.ofVirtual()" instead of "Thread.ofPlatform()"). No more golang envy for sure.

Depending on how much memory is used by the Thread stack (presumably 1M-512K by default, allegedly 128K with Alpine base images) that's your 1G-500M heap space usage improvement right off the bat.

The migration from JDK17 to JDK21 was uneventful in production. The only issue is limited monitoring as a thread dump will not show most virtual threads and the micrometer metrics will not even collect the total number of active virtual threads. It's supposed to work better in JDK24.

The Spring Framework directly supports virtual threads with "spring.threads.virtual.enabled=true" but I haven't tried it to comment.