Java Performance

pluginagentmarketplace/custom-plugin-java

A focused toolkit for JVM performance work that covers the essentials: GC tuning presets for different scenarios (G1, ZGC, Serial), profiling commands using jstack and jmap, and JMH benchmarking setup. The quick reference format is solid here because performance tuning is usually urgent and you need the right flags fast. It's bonded as a secondary skill to an advanced Java agent, which makes sense since you're typically optimizing existing code rather than writing from scratch. The GC comparison table is genuinely useful for deciding between collectors based on your heap size and latency requirements. Most valuable when you're facing memory leaks, GC pauses, or need to optimize container deployments where resource constraints matter.

skills.sh installs: 488
GitHub stars: 42
last updated: Aug 21, 2026

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Install

$ npx -y skills add pluginagentmarketplace/custom-plugin-java --skill java-performance --agent claude-code

Installs into .claude/skills of the current project.

Files

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>