ReddRadar
Agent skill
java-performance
JVM performance tuning - GC optimization, profiling, memory analysis, benchmarking
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/productivity/java-performance
SKILL.md
Java Performance Skill
Optimize JVM performance through profiling, GC tuning, and memory analysis.
Overview
This skill covers JVM performance optimization including garbage collection tuning, memory analysis, CPU profiling, and benchmarking with JMH.
When to Use This Skill
Use when you need to:
- Tune GC for low latency or throughput
- Profile CPU hotspots
- Analyze memory leaks
- Benchmark code performance
- Optimize container settings
Quick Reference
GC Presets
# High-throughput
-XX:+UseG1GC
-XX:MaxGCPauseMillis=200
-Xms4g -Xmx4g
-XX:+AlwaysPreTouch
# Low-latency
-XX:+UseZGC
-XX:+ZGenerational
-Xms8g -Xmx8g
# Memory-constrained
-XX:+UseSerialGC
-Xms512m -Xmx512m
-XX:+UseCompressedOops
# Container-optimized
-XX:+UseContainerSupport
-XX:MaxRAMPercentage=75.0
-XX:+ExitOnOutOfMemoryError
Profiling Commands
# Thread dump
jstack -l <pid> > threaddump.txt
# Heap dump
jmap -dump:format=b,file=heap.hprof <pid>
# GC analysis
jstat -gcutil <pid> 1000 10
# Flight recording
jcmd <pid> JFR.start duration=60s filename=app.jfr
# Async profiler
./profiler.sh -d 30 -f profile.html <pid>
JMH Benchmark
@BenchmarkMode(Mode.Throughput)
@Warmup(iterations = 3, time = 1)
@Measurement(iterations = 5, time = 1)
@State(Scope.Benchmark)
public class MyBenchmark {
@Benchmark
public void testMethod(Blackhole bh) {
bh.consume(compute());
}
}
GC Comparison
| GC | Latency | Throughput | Heap Size |
|---|---|---|---|
| G1 | Medium | High | 4-32GB |
| ZGC | Very Low | Medium | 8GB-16TB |
| Shenandoah | Very Low | Medium | 8GB+ |
| Parallel | High | Very High | Any |
Troubleshooting
| Problem | Cause | Solution |
|---|---|---|
| GC thrashing | Heap too small | Increase heap |
| High latency | GC pauses | Switch to ZGC |
| Memory leak | Object retention | Heap dump + MAT |
| CPU spikes | Hot loops | Profile + optimize |
Usage
Skill("java-performance")
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
majiayu000/claude-skill-registry
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
majiayu000/claude-skill-registry
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
majiayu000/claude-skill-registry
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
majiayu000/claude-skill-registry
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
majiayu000/claude-skill-registry
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
majiayu000/claude-skill-registry
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
Didn't find tool you were looking for?