RFR: 8364361: [process] java.lang.Process should implement Closeable [v12]

[Naoto Sato]

On Mon, 29 Sep 2025 20:42:38 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> The teardown of a Process launched by `ProcessBuilder` includes the closing of streams and ensuring the termination of the process is the responsibility of the caller. The `Process.close()` method provides a clear and obvious way to ensure all the streams are closed and the process terminated.
>> 
>> The try-with-resources statement is frequently used to open streams and ensure they are closed on exiting the block. By implementing `AutoClosable.close()` the completeness of closing the streams and process termination can be done by try-with-resources.
>> 
>> The actions of the `close()` method are to close each stream and destroy the process if it has not terminated.
>
> Roger Riggs 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 16 additional commits since the last revision:
> 
>  - Merge branch 'master' into 8364361-process-autocloseable
>  - Address review comments for code and javadoc in Process, the test and the example.
>    Reinforced that calling waitFor should occur before calling close to wait for termination and get the exitStatus.
>    Corrected the error message check for invalid handles on Windows.
>    Update test to allow normal completion when exceptions may be expected.
>    Correct the expected message on Windows for an invalid handle exception.
>  - Update close() to use "terminate" consistently.
>  - Remove volatile from "closed" field; updates are guarded by synchronized.
>  - The CSR review prompted the expansion of the description of responsibilities
>    of subclasses of Process to invoke `super.close()` if overriding the `close()` method.
>  - Monor improvements to javadoc, move close() near the constructor
>    to make it more prominent in the javadoc.
>  - Merge branch 'master' into 8364361-process-autocloseable
>  - Expand the description of close() to describe the behavior of destroying the process.
>  - javadoc tweaks
>  - Misc, javadoc cleanup
>    Simplified the Interrupt handling in ProcessCloseTest.ProcessCommand.ExpectExit.
>  - ... and 6 more: https://git.openjdk.org/jdk/compare/2aa98b7e...5a0c5602

Still look good. A couple of nits

test/jdk/java/lang/Process/ProcessCloseTest.java line 318:

> 316:         private static void stderrExpectPolo(Process p) {
> 317:             String line = readLine(p.getErrorStream());
> 318:             Assertions.assertEquals("Polo", line, "Stderr Expected Polo");        }

Curly bracket needs a new line

test/jdk/java/lang/Process/ProcessCloseTest.java line 571:

> 569:     /*
> 570:      * Invasive hack to force closing a FileDescriptor to throw an exception on FileDescriptor.close().
> 571:      * The output stream is pealed back to get the FileDescriptor containing the fd or handle.

output -> input

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PR Review: https://git.openjdk.org/jdk/pull/26649#pullrequestreview-3285786463
PR Review Comment: https://git.openjdk.org/jdk/pull/26649#discussion_r2392163950
PR Review Comment: https://git.openjdk.org/jdk/pull/26649#discussion_r2392167896