review request: 4244896: (process) Provide System.getPid(), System.killProcess(String pid)
rob.mckenna at oracle.com
Thu May 31 16:48:54 UTC 2012
That link should be:
On 31/05/12 16:05, Rob McKenna wrote:
> Latest version including work on the spec language:
> On 10/05/12 19:56, Rob McKenna wrote:
>> Hi folks,
>> The latest version is at:
>> Feedback greatly appreciated.
>> On 19/04/12 12:05, Alan Bateman wrote:
>>> On 19/04/2012 01:05, David Holmes wrote:
>>>> On 18/04/2012 11:44 PM, Jason Mehrens wrote:
>>>>> It looks like waitFor is calling Object.wait(long) without owning
>>>>> this objects monitor. If I pass Long.MAX_VALUE to waitFor,
>>>>> shouldn't waitFor return if the early if the process ends?
>>>> Also waitFor doesn't call wait() under the guard of a looping
>>>> predicate so it will suffer from lost signals and potentially
>>>> spurious wakeups. I also don't see anything calling notify[All] to
>>>> indicate the process has now terminated. It would appear that
>>>> wait(timeout) is being used as a sleep mechanism and that is wrong
>>>> on a number of levels.
>>> I assume waitFor(timout) will require 3 distinct implementations,
>>> one for Solaris/Linux/Mac, another for Windows, and a default
>>> implementations for Process implementations that exist outside of
>>> the JDK.
>>> It's likely the Solaris/Linux/Mac implementation will involve two
>>> threads, one to block in waitpid and the other to interrupt it via a
>>> signal if the timeout elapses before the child terminates. The
>>> Windows implementation should be trivial because it can be a timed
>>> I assume the default implementation (which is what is being
>>> discussed here) will need to loop calling exitValue until the
>>> timeout elapses or the child terminates. Not very efficient but at
>>> least it won't be used when when creating Processes via Runtime.exec
>>> or ProcessBuilder.
>>> I think the question we need to consider is whether waitFor(timeout)
>>> is really needed. If it's something that it pushed out for another
>>> day then it brings up the question as to whether to include isAlive
>>> now or not (as waitFor without timeout gives us an isAlive
>>> equivalent too).
More information about the core-libs-dev