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motoboi • today at 2:27 PM • 4 replies • view on HN

I found claude and GPT very helpful on this, because java have a very sofisticated monitoring harness. Just ask the agent to connect to the running application (on kubernetes or whatever) on prod and do a java flight recording then analyze allocations.

I managed to improve some applications of ours from several garbage collections per second to several minutes between collections. That _really_ improves p99.

Replies

haglin • today at 3:18 PM

I work on OpenJDK, so I may be biased, but I’ve also found that JFR works really well with LLMs.

  $ java -XX:StartFlightRecording:maxsize=10M,filename=dump.jfr -jar app.jar

  $ jfr view all-views dump.jfr > report.txt

  $ jfr print dump.jfr > all.txt
Then ask Codex, or whatever AI tool you use, to analyze report.txt for issues and use all.txt to dig deeper, if needed.
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exabrial • today at 3:30 PM

Take a peek at jolokia if you've never used it :) Attach it as a JVM agent to _any_ process to expose it's JMX attributes as http calls, and it even gives you a neat little console to log into.

If you want to collect these, telegraf has a jolokia plugin. It's an incredible combination!

declan_roberts • today at 3:06 PM

That sounds like a great idea. What kind of prompt do you use?

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wmichelin • today at 2:43 PM

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