On Sun, 15 Feb 2026 06:01:02 GMT, Ioi Lam <[email protected]> wrote:

>> The bug is here on line 121:
>> 
>> https://github.com/openjdk/jdk/blob/586846b84a38d285c5905437e903cfc57f609410/src/java.base/windows/classes/java/lang/ProcessImpl.java#L118-L121
>> 
>> If `System.out` has been closed, `fdAccess.getHandle()` will return -1. This 
>> causes `stdHandles[1]` to have the same value as if the child process's 
>> stdout was redirected with `Redirect.PIPE`. This will cause a Pipe to be 
>> created here for the child process's STDOUT on line 168:
>> 
>> https://github.com/openjdk/jdk/blob/586846b84a38d285c5905437e903cfc57f609410/src/java.base/windows/native/libjava/ProcessImpl_md.c#L158-L184
>> 
>> However, the caller of the `ProcessBuilder` is not aware of this and will 
>> not drain this pipe. This causes the child process to get stuck when writing 
>> to its stdout when the pipe 's buffer is filled up.
>> 
>> The fix is to treat the redirection as `Redirect.DISCARD` when `System.out` 
>> and/or `System.err` have been closed.
>
> Ioi Lam 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 11 additional commits since the 
> last revision:
> 
>  - Review comment by @AlanBateman: use implNote instead. Also fixed 
> whitespaces
>  - Merge branch 'master' into 
> 8366736-closed-system-out-causes-child-process-to-hang-on-windows
>  - @RogerRiggs review comments
>  - Fixed typo
>  - fixed typo
>  - Merge branch 'master' into 
> 8366736-closed-system-out-causes-child-process-to-hang-on-windows
>  - Review comments from @RogerRiggs
>  - Reverted previous unintended commit
>  - 8375654: Exclude all array classes from dynamic CDS archive
>  - Review comments from @RogerRiggs
>  - ... and 1 more: https://git.openjdk.org/jdk/compare/6d00da44...bc999867

Looks good.

-------------

Marked as reviewed by rriggs (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29198#pullrequestreview-3805643832

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