Q&A
Q&AHow do you troubleshoot high thread contention in Java?
Use repeated thread dumps and lock profiling to locate hot locks, then reduce serialization safely.
Read the concise answer
Capture repeated thread dumps and identify many threads blocked on the same owner or monitor. Use a profiler or JFR lock events to quantify contention and critical-section time. Reduce lock scope, shard independent state, batch updates, or use concurrent primitives only when they preserve the invariant; verify throughput and correctness under representative load.