Parallel stream blocks common pool
A Java service handles most requests fine, but a subset of requests that fan out work using `list.parallelStream()...` intermittently hang for many seconds across the WHOLE service — even simple requests that don't use parallel streams slow down at the same time. CPU is moderate. A thread dump shows the JVM's ForkJoinPool.commonPool worker threads all parked/blocked inside network or DB calls. A recent change added a blocking remote call inside the lambda passed to a `parallelStream()`. How do you triage and mitigate?
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 40 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.