RFR: 8376052: Use AttachOperationFailedException rather than AttachNotSupportedException in findTargetProcessTmpDirectory() [v2]

[Yasumasa Suenaga]

On Thu, 22 Jan 2026 12:09:28 GMT, Alan Bateman <alanb at openjdk.org> wrote:

> Can you please provide an example where IOException is thrown? 

I could not produce IOException, but it might occur if filesystem is broken.
AccessDeniedException would happen as following. We can see it easy on attach to rootless container.

# ./jcmd 1 VM.version
1:
java.nio.file.AccessDeniedException: /proc/1/root/tmp
        at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:90)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:108)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:113)
        at java.base/sun.nio.fs.UnixFileSystemProvider.isSameFile(UnixFileSystemProvider.java:391)
        at java.base/java.nio.file.Files.isSameFile(Files.java:1418)
        at jdk.attach/sun.tools.attach.VirtualMachineImpl.findTargetProcessTmpDirectory(VirtualMachineImpl.java:280)
        at jdk.attach/sun.tools.attach.VirtualMachineImpl.findSocketFile(VirtualMachineImpl.java:236)
        at jdk.attach/sun.tools.attach.VirtualMachineImpl.<init>(VirtualMachineImpl.java:87)
        at jdk.attach/sun.tools.attach.AttachProviderImpl.attachVirtualMachine(AttachProviderImpl.java:56)
        at jdk.attach/com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:201)
        at jdk.jcmd/sun.tools.jcmd.JCmd.executeCommandForPid(JCmd.java:113)
        at jdk.jcmd/sun.tools.jcmd.JCmd.main(JCmd.java:97)


> It would be useful to get an example or two of when MonitorException is thrown. 

As I said before, I cannot find out the location to throw MonitorException in JDK source around attach mechanism, but it might happen if the user uses custom attach provider. Anyway it is checked exception, so it shouldn't ignore or raise assertion error.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29355#discussion_r2716993417