I vibe-coded jvm-hotpath to analyse my vibe-coded output.

jvm-hotpath is a JVM agent that instruments Java code and records line-level execution counts. The differentiator is the UX: it generates a single HTML report that updates continuously while your app is running. No server/dashboard — it uses JSONP + polling, so you can open it from file:// and watch hotspots move as you click around. It’s meant for local dev, and there’s a stopwatch-style lap/reset so you can zero counts, do one action, and immediately see the hot path for just that interaction.

Why this helps with “vibe coding”: when code is changing faster than your understanding (LLM-assisted or just a new/unfamiliar codebase), the hard bit is answering “what actually ran when I did this?”. This gives a quick runtime map of the paths you really exercised — and it’s also a handy way to learn a codebase by driving the app and watching what lights up.

Questions I’m curious about:

• What’s the closest thing you’ve seen to this in the JVM world?

• Where would this save you the most time: learning a new codebase, validating AI-assisted changes, refactoring safely, or chasing weird behaviour?

Project: https://github.com/sfkamath/jvm-hotpath

Documentation (README): https://github.com/sfkamath/jvm-hotpath/blob/main/README.md

Motivation: https://github.com/sfkamath/jvm-hotpath/blob/main/docs/Motiv...

Foojay article: https://foojay.io/today/runtime-code-analysis-in-the-age-of-...

Long-time HN reader, first time posting — happy to take feedback.

user:	sfkamath
created:	May 12, 2013
karma:	2
about:	http://about.me/sfk

1.	Show HN: JVM hot-path execution analysis for Java in the age of vibe coding(github.com) 4 points by sfkamath 93 days ago \| 4 comments
2.	How CIOs can adapt to embrace developer-led innovation(thenextweb.com) 1 points by sfkamath 11 years ago \| 0 comments
3.	Show HN: How far can an indian passport take you....(bit.ly) 1 points by sfkamath 13 years ago \| -1 comments