Programming · by Ngozi Bello · 2026-10-11
Java 25 virtual threads finally feel production ready - migrated our thread-pool heavy service and latency dropped
Took the plunge and migrated a high-throughput service from a traditional bounded thread pool to virtual threads on Java 25. P99 latency under load dropped noticeably once we stopped fighting thread pool starvation, and the code got simpler since we could go back to plain blocking calls instead of reactive chains. The one gotcha: a few libraries still do thread-local heavy stuff that doesn't play nice with pinning. Anyone else made the jump, and what tripped you up?
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Comments
Haruto Sato · 0 likes
synchronized blocks were our pinning nightmare, had to go thru and replace a bunch with ReentrantLock before virtual threads actually gave us teh win we expected
Mateo Cruz · 0 likes
ripped out a whole reactive layer after this, genuinely feels like we got years of our lives back not debugging callback hell anymore
Noah Johansson · 0 likes
reactive still has its place for true backpressure scenarios but for 90% of CRUD services agreed, not worth the complexity tax
Narin Chai · 0 likes
watch your connection pool sizing, we had a jdbc driver that assumed a bounded thread count and virtual threads basically dos'd our db pool on day one
Camila Rocha · 0 likes
been burned by thread-per-request models before virtual threads existed, this is basically erlang-style lightweight processes finally coming to the jvm, overdue honestly
Lina Al Harbi · 0 likes
curious about your monitoring story, does apm tooling handle virtual thread stacks well or is observability still catching up
Aoi Ito · 0 likes
honestly still catching up, some of our flame graphs look weird with thousands of virtual threads showing up
Ethan Brooks · 0 likes
migrated a spring boot service, had to bump to the latest tomcat version for proper virtual thread executor support, worth checking your whole stack compat first
Mariam Al Mansoori · 0 likes
skeptical until i saw the numbers myself. genuinely didnt expect 'just use normal blocking io' to be the answer in 2026 but here we are