[crac] RFR: 8377562: [CRaC] Add better logging to RemoteJmxTest [v2]

[Timofei Pushkin]

On Tue, 10 Feb 2026 18:00:50 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

>> Timofei Pushkin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
>> 
>>  - Ensure resources live long enough in some tests
>>  - Merge remote-tracking branch 'openjdk-crac/crac' into remote-jmx-test
>>  - Always capture output
>>  - Improve process synchronization in ImageScoreTest
>>  - Make timed waiting more robust
>>  - Merge remote-tracking branch 'openjdk-crac/crac' into remote-jmx-test
>>  - Refactor CracProcess to allow multi-waiting
>>  - Add better logging to RemoteJmxTest
>
> test/jdk/jdk/crac/RemoteJmxTest.java line 83:
> 
>> 81:                         System.out.println("[CHILD STDOUT] " + line);
>> 82:                         if (!bootedFuture.isDone()) {
>> 83:                             if (BOOTED.equals(line)) bootedFuture.complete(null);
> 
> This code looks like as if you expect that the messages could be printed multiple times; if that happens this should fail the test (for simplicity I wouldn't mind if it fails by timeout in the end, though, as long as the reason is printed earlier in the log).
> 
> I wonder if this could be consolidated with `CracProcess.waitForStdout()` (the least the lines are prefixed here. Maybe the best interface would be
> 
> CountDownLatch<Void> watch(String line, boolean positiveMatch);
> 
> (called repeatedly to get multiple latches), and `waitForStdout` would use that.

I wanted to use `waitForStdout` initially as well but with the existing implementation it is not possible to use multiple calls to `watch`/`waitForStdout`/`outputAnalyzer` — only the first of such calls will receive the output.

I've refactored our test code now (+ did some cleanup) but since it is pretty big it'll probably require a few fixups so I'm converting this to draft for now.

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PR Review Comment: https://git.openjdk.org/crac/pull/295#discussion_r2799275575