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From Gregory Shimansky <gshiman...@gmail.com>
Subject Re: [classlib] Intermittent failures of UDP tests
Date Tue, 13 Feb 2007 18:34:19 GMT
Mikhail Markov wrote:
> Hi!
> 
> As you've probably noticed, sometimes we have a failures in Datagram* tests
> (i.e. tests using UDP protocol like DatagramChannelTest, DatagramSocketTest
> etc.)
> See the beginning of the story here:
> http://issues.apache.org/jira/browse/HARMONY-2338 and the discussion here:
> http://comments.gmane.org/gmane.comp.java.harmony.devel/20884.
> 
> Now we have the following scheme for random (not-busy) ports generation for
> java.net tests: use ServerSocket(0);
> It works for TCP sockets, but for UDP sockets it sometimes fails as
> operating system sometimes closes this ServerSocket too slowly so the code
> trying to use this port gets "The address is already in use" kind of
> exception (HARMONY-2860, HARMONY-3046, HARMONY-3156).

I don't quite get it. Is it operating system to be blamed or the code 
for ServerSocket(0) which returns a port that is still used by some socket?

> I've tried to implement the same approach but use new DatagramSocket() for
> obtaining random port number for UDP tests (added it as a patch for
> HARMONY-2860), but it also fails sometimes.
> 
> So, based on the previous discussions, we'll probably have 2 options of
> fixing UDP tests without their re-writing:
>  - Reserve several ports numbers and use them in cycle
>  - Add the delay after obtaining the not-busy port (and hope that other
> processes will not take this port while we're sleeping :-))
> 
> The 1-st from the above seems the most attractive choice.
> The related questions:
>  1) How may reserved ports do we need? IMHO, 3 for the beginning will be
> enough
>  2) What are exact numbers: Alexey Petrenko suggested starting from 63527
> :-) Other options?
> 
> Thoughts?
> 
> If nobody objects i'll try to implement this scheme for port obtaining for
> UDP tests.
> 
> Regards,
> Mikhail
> 


-- 
Gregory


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