Integrated: 8352533: Report useful IOExceptions when jspawnhelper fails

[Aleksey Shipilev]

On Fri, 21 Mar 2025 10:00:26 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> When jspawnhelper fails for whatever reason, but more prominently due to [JDK-8325621](https://bugs.openjdk.org/browse/JDK-8325621), it will report the errors into stdout, but not to the relevant `IOException`. So, if the application is configured to only capture the exception logs (e.g. through `java.util.logging`), we will miss any output from `jspawnhelper`, and user would be left without a clue what have happened. We have seen customers spending weeks trying to figure out what went wrong.
> 
> It would be good to provide useful `IOException` when `jspawnhelper` fails. We already have a precedent with vmError [printing helpful suggestions](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/utilities/vmError.cpp#L422) when VM fails, we can do a similar thing here. 
> 
> I am very open to bike-shedding about the actual message :)
> 
> Additional testing:
>  - [x] Ad-hoc experiments with breaking jspawnhelper
>  - [x] macos-aarch64-server-fastdebug, `java/lang/Process java/lang/ProcessBuilder`

This pull request has now been integrated.

Changeset: 5c73dfc2
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/5c73dfc28cbd6801ac85c6685fb8c77aad3ab0b7
Stats:     100 lines in 3 files changed: 74 ins; 0 del; 26 mod

8352533: Report useful IOExceptions when jspawnhelper fails

Reviewed-by: simonis, rriggs, stuefe

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PR: https://git.openjdk.org/jdk/pull/24149