RFR: 8357914: TestEmptyBootstrapMethodsAttr.java fails when run with TEST_THREAD_FACTORY=Virtual [v2]

[Leonid Mesnik]

On Thu, 5 Jun 2025 04:43:47 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> Please review this small test fix. The test launches a child process with the only purpose of validating that the load of the main class (`emptynumbootstrapmethods1`/`emptynumbootstrapmethods2`) completes successfully and doesn’t throw `ClassFormatError`. The class doesn’t define a main method, so later during execution of `LauncherHelper.validateMainMethod` the child VM exits with the following error message which we check from the `OutputAnalyzer` output:
>> 
>> 
>> Error: Main method not found in class emptynumbootstrapmethods1, please define the main method as:
>>    public static void main(String[] args)
>> or a JavaFX application class must extend javafx.application.Application
>> 
>> 
>> The issue when the test is run with `TEST_THREAD_FACTORY=Virtual` is that loading of `emptynumbootstrapmethods1` is done in `jdk.test.lib.process.ProcessTools.main` (the actual entry point), which instead of calling `MethodFinder.findMainMethod(mainClass)` and aborting if result is null like `LauncherHelper` uses
>> `Method mainMethod = c.getMethod("main", new Class<?>[] { String[].class });` which throws an exception instead and the test exits with the following error message:
>> 
>> 
>> [Exception in thread "main" java.lang.NoSuchMethodException: emptynumbootstrapmethods1.main([Ljava.lang.String;)
>> at java.base/java.lang.Class.getMethod(Class.java:2166)
>> at jdk.test.lib.process.ProcessTools.main(ProcessTools.java:984)
>> 
>> 
>> The proposed fix adjusts the output we check for based on whether the test was run on a platform thread or a virtual thread.
>> 
>> Thanks,
>> Patricio
>
> Patricio Chilano Mateo has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Check vthread case on child's VM command

I think to add support in test library to find the mode. 
So I'll replace checks along the test code test.thread.factory with library method later.

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Marked as reviewed by lmesnik (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/25509#pullrequestreview-2900688005