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` ------------- Commit messages: - Initial fix Changes: https://git.openjdk.org/jdk/pull/24149/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24149&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8352533 Stats: 57 lines in 2 files changed: 41 ins; 0 del; 16 mod Patch: https://git.openjdk.org/jdk/pull/24149.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/24149/head:pull/24149 PR: https://git.openjdk.org/jdk/pull/24149
