Java high CPU usage
High CPU in Java is often a mix of hot methods, GC behavior, lock contention, and thread scheduling overhead.
Common symptoms
- JVM process stays hot under load
- Latency increases across requests
- CPU rises without proportional throughput
Likely causes
- Hot code path under load
- Excessive garbage collection
- Too many threads or lock contention
Evidence to look for
Java PID dominates CPU
Thread count rises along with CPU
Sampling points to a narrow set of methods
What it usually means
The fix depends on whether the JVM is spending time doing useful compute, garbage collection, or synchronization overhead.
What to do next
- 1Inspect thread and GC behavior alongside CPU
- 2Profile hot methods before tuning blindly
- 3Reduce thread contention and expensive allocations
See what's causing your CPU
cpum.ai turns CPU, process, disk, and memory signals into plain-English explanations with evidence.
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