RFR: 8356870: HotSpotDiagnosticMXBean.dumpThreads and jcmd Thread.dump_to_file updates
Alan Bateman
alanb at openjdk.org
Sat May 24 07:40:12 UTC 2025
Updates the thread dump generated by HotSpotDiagnosticMXBean.dumpThreads and jcmd Thread.dump_to_file to include thread state and lock information. Also update the HotSpotDiagnosticMXBean.dumpThreads API description to link to a description of the JSON format dump as that format is intended to be parseable/read by tools.
This PR is dependent on [pull/25425](https://github.com/openjdk/jdk/pull/25425). As noted in that PR, the changes accumulated in the loom repo, and have been split up to make it easier to review.
The changes include some re-implementation of ThreadDumper. This is because it used PrintStream and didn't didn't fail if there was an I/O error, e.g. file system full. Furthermore, the indentation to pretty print the json was fragile and hard to maintain so this is changed to use a supporting writer class to do this.
Test coverage is significantly expanded, including updating the test library that is used by several tests to parse the thread dump.
Testing: tier1-6
-------------
Commit messages:
- Initial commit
- initial fix
Changes: https://git.openjdk.org/jdk/pull/25429/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25429&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8356870
Stats: 2407 lines in 16 files changed: 1985 ins; 125 del; 297 mod
Patch: https://git.openjdk.org/jdk/pull/25429.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/25429/head:pull/25429
PR: https://git.openjdk.org/jdk/pull/25429
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