Java Flight Recorder
Hacker ApprovedRanked 2 of 9 profilers by recommenders
People recommend it as a free, low-overhead profiler and telemetry tool for diagnosing Java performance and memory problems, including in production. No critic in these quotes names a caveat.
People recommend it as a free, low-overhead profiler and telemetry tool for diagnosing Java performance and memory problems, including in production. No critic in these quotes names a caveat.
10 people gave an opinion
- recommend it
- 10
- criticize it
- 0
- approval share
- 100%
Recommended in 6 of 13 months
- November 2025: recommended
- December 2025: not recommended
- January 2026: not recommended
- February 2026: not recommended
- March 2026: recommended
- April 2026: not recommended
- May 2026: not recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: not recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 10 people recommend itNeeds 10 or more, met.
- Nobody criticizes itNeeds 2 to 1 or better, met.
- Recommended in 6 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Low-overhead profiling suitable for production
“It's hard to compete with JFR on the breadth and depth of low-overhead, in production telemetry”
Comment from 15 Sep 2026 in “Java 27” “attach a debugger to a live prod system with minimal overhead”
Comment from 25 Nov 2025 in “A million ways to die from a data race in Go” “minimal ~1% performance overhead”
Comment from 20 Mar 2026 in “Java 26 is here, and with it a solid foundation for the future” Deep, broad telemetry and diagnostics
“It's hard to compete with JFR on the breadth and depth of low-overhead, in production telemetry”
Comment from 15 Sep 2026 in “Java 27” “It's depth and breadth are unmatched.”
Comment from 18 Oct 2026 in “JDK 28”
Other profilers people recommend
The four most recommended other profilers, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| perf | 13 | 4 | 76% | 8 | — | Approved |
| Java Flight RecorderThis page | 10 | 0 | 100% | 6 | — | Approved |
| Instruments | 9 | 2 | 82% | 5 | — | — |
| Perfetto | 8 | 2 | 80% | 4 | — | — |
| Python 3.15 sampling profiler | 6 | 1 | 86% | 3 | — | — |
What people said
9 of the 12 comments that mention it, newest first. Each links to the original comment.
“It's depth and breadth are unmatched.”
“Observability on the JVM is second to none, especially with tools like JFR available for free.”
“It's hard to compete with JFR on the breadth and depth of low-overhead, in production telemetry”
“I've also found that JFR works really well with LLMs”
“do a java flight recording then analyze allocations”
“the first step is profiling (JFRs and heap dumps) to see where memory is spent and what is dominating the allocation rate”
“minimal ~1% performance overhead”
“Such good tooling to figure out whatever it is you are having problems with in production.”
“attach a debugger to a live prod system with minimal overhead”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.