# Java Flight Recorder

10 Hacker News commenters recommended Java Flight Recorder and 0 criticized it, November 2025 to November 2026. It was recommended in 6 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** 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.

## Why people recommend it

- Low-overhead profiling suitable for production (3 comments): "It's hard to compete with JFR on the breadth and depth of low-overhead, in production telemetry" ([source](https://news.ycombinator.com/item?id=49714195)) "attach a debugger to a live prod system with minimal overhead" ([source](https://news.ycombinator.com/item?id=46043337)) "minimal ~1% performance overhead" ([source](https://news.ycombinator.com/item?id=47459049))
- Deep, broad telemetry and diagnostics (2 comments): "It's hard to compete with JFR on the breadth and depth of low-overhead, in production telemetry" ([source](https://news.ycombinator.com/item?id=49714195)) "It's depth and breadth are unmatched." ([source](https://news.ycombinator.com/item?id=50137633))

## Alternatives hackers recommend

- [perf](https://hackerapproved.com/p/perf.md): 13 recommend
- [Instruments](https://hackerapproved.com/p/instruments.md): 9 recommend
- [Perfetto](https://hackerapproved.com/p/perfetto.md): 8 recommend
- [Python 3.15 sampling profiler](https://hackerapproved.com/p/python-3-15-sampling-profiler.md): 6 recommend
- [Heaptrack](https://hackerapproved.com/p/heaptrack.md): 5 recommend

## Cite as

Hacker Approved, "Java Flight Recorder", https://hackerapproved.com/p/java-flight-recorder/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).