161 Java Profiling Detect Agent Skill

Use when you need to set up Java application profiling to detect and measure performance issues — including trusted preinstalled async-profiler v4.x setup, problem-driven profiling (CPU, memory, threading, GC, I/O), interactive profiling scripts, JFR integration with Java 25 (JEP 518, JEP 520), or collecting profiling data with flamegraphs and JFR recordings. This should trigger for requests such as Improve the code with profiling; Apply Profiling; Refactor the code with profiling; Add profiling support; Collect JFR or async-profiler data for Java performance. Part of Plinth Toolkit

23k tokens

context cost

the whole folder, loaded on every use

files

ships runnable scripts

copies elsewhere

how many repositories repackaged it

423

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/jabrena/plinth --skill 161-java-profiling-detect

The instruction itself

5 sections, as written by the author

Java Profiling Workflow / Step 1 / Collect data to measure potential issues

Set up the Java profiling detection phase using a trusted preinstalled async-profiler v4.x, problem-driven interactive profiling scripts, and comprehensive data collection for CPU hotspots, memory leaks, lock contention, GC issues, and I/O bottlenecks. Uses JEP 518 (Cooperative Sampling) and JEP 520 (Method Timing) for reduced overhead.

What is covered in this Skill?

Run application with profiling JVM flags (run-java-process-for-profiling.sh)
Interactive profiling script (profiler/scripts/profile-java-process.sh) — copy exact template
Directory structure: profiler/scripts/, profiler/results/, profiler/current/
Automated OS/architecture detection and trusted preinstalled async-profiler validation
CPU, memory, lock, GC, I/O profiling modes
Flamegraph and JFR output with timestamped results

Scope: Use the exact bash script templates without modification or interpretation.

Constraints

Copy bash scripts exactly from templates. Ensure JVM flags are applied for profiling compatibility. Verify Java processes are running before attaching profiler.

CRITICAL: Copy the bash script templates exactly — do not modify, interpret, or enhance
SETUP: Create profiler directory structure: profiler/scripts, profiler/results
SUPPLY CHAIN: Do not download profiler binaries at runtime; require ASYNC_PROFILER_HOME or profiler/current to point to a trusted, preinstalled async-profiler distribution
EXECUTABLE: Make scripts executable with chmod +x
BEFORE APPLYING: Read the reference for exact script templates and setup instructions
EDGE CASE: If request scope is ambiguous, stop and ask a clarifying question before applying changes
EDGE CASE: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance

When to use this skill

Improve the code with profiling
Apply Profiling
Refactor the code with profiling
Add profiling support
Collect JFR or async-profiler data for Java performance

Workflow

Read profiling setup reference

Read references/161-java-profiling-detect.md and use script templates exactly as provided.

Create profiler workspace and scripts

Create profiler/scripts and profiler/results, copy setup/profile scripts verbatim, and make scripts executable.

Run application with profiling compatibility

Start Java process with required profiling JVM flags and verify target process availability for profiler attachment.

Collect profiling artifacts

Capture CPU/memory/lock/GC/I/O data and produce timestamped flamegraph and JFR outputs for analysis.

Reference

For detailed guidance, examples, and constraints, see references/161-java-profiling-detect.md.

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How to use it

Copy the folder

Take jabrena/161-java-profiling-detect from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.