On Wed, 14 Jan 2026 03:22:33 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 incrementally with one additional commit > since the last revision: > > Review comments from @RogerRiggs
The change in behavior should be documented in an APINote on Process.inheritIO() to say that the output is discarded if it has been closed. ------------- PR Comment: https://git.openjdk.org/jdk/pull/29198#issuecomment-3749879254
