[SNMP4J] BindException: Address already in use, even with reuseAddress=true (with proposed fix)

[Frank Fock]

Hi Thomas,

If you set the socket timeout to a value >0 (which is recommended), then
the worker thread is joined on the close().
If the timeout is 0, no join is performed because otherwise a deadlock 
would occur
if the interrupt call is triggered by the close() method while the 
worker thread
is not in the select method (i.e., waiting on IO).

Thus, I would not change the existing code.

Best regards,
Frank

Am 26.05.2015 um 22:13 schrieb Thomas L:
> Hello,
>
> I think I have found a bug in SNMP4J (2.3.3) where we can have a "BindException: Address already in use" exception when creating a DefaultUdpTransportMapping, whereas reuseAddress=true, if we have previously created and closed a similar DefaultUdpTransportMapping.
> In DefaultUdpTransportMapping.close(), the listener thread (WorkerTask) is not "joined", so it can still use the UDP port for some time, and creating a new DefaultUdpTransportMapping on the same port, even if reuseAddress=true, is not possible.
> My current dirty workaround is to access the "WorkerTask" field by reflection just before closing the Snmp object, and then calling "join()" on the object, so I am sure the thread is correctly terminated before any new attempt to create a new DefaultUdpTransportMapping.
>
> Can this problem be solved in the next version of SNM4J?
>
> Regards,
> Thomas
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