Differences in Process#destroy() between Windows and Unix implementations

[David Holmes]

Hi Andreas,

On 10/11/2010 5:31 AM, Andreas Kohn wrote:
> there seems to be a difference in behavior between Process#destroy()
> implementations on Windows and !Windows: on Windows TerminateProcess()
> [1] is called, which gives the process no way to react or in any way
> intercept the termination, while on Unix a simple SIGTERM is send which
> the process can just decide to ignore. [2]
>
> Is this intentional?

As I understand it: yes and no. :)

The problem is that neither version is necessarily what you always want. 
SIGTERM is nice in that it allows the process to execute cleanup handlers 
etc (such as an exec'ed JVM!) but I don't think Windows has an equivalent, 
so we have to use TerminateProcess. On the flip side if SIGTERM fails we 
have no way to really kill an errant process.

What we really need is two destroy methods: one that tries to terminate 
nicely and one with "extrene prejudice". But again I'm not sure that Windows 
would support that. I suppose we could also define the destroy() method to 
try both approaches, if available, eg SIGTERM wait a while SIGKILL. But then 
we need a way to specify "wait a while".

David Holmes

> I do prefer the Windows behavior, mainly because I do create processes
> once in a while that simply fail to terminate due to bugs in their
> implementation, and having Process#destroy() as a last, and terminal,
> resort is very helpful to work-around those issues.
>
> Regards,
> --
> Andreas
>
> [1]
> http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/d87c1c06bbf9/src/windows/native/java/lang/ProcessImpl_md.c
> [2]
> http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/d87c1c06bbf9/src/solaris/native/java/lang/UNIXProcess_md.c
>
>