161-java-profiling-detect

name	161-java-profiling-detect
description	Use when you need to set up Java application profiling to detect and measure performance issues — including automated async-profiler v4.0 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. Part of the skills-for-java project
license	Apache-2.0
metadata	{"author":"Juan Antonio Breña Moral","version":"0.13.0-SNAPSHOT"}

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

Set up the Java profiling detection phase: automated environment setup with async-profiler v4.0, 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 async-profiler download
• 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
• EXECUTABLE: Make scripts executable with chmod +x
• BEFORE APPLYING: Read the reference for exact script templates and setup instructions

When to use this skill

• Review Java code for profiling
• Add profiling support

Reference

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