select() returns empty key set

[Alan Bateman]

Robert Larsen wrote:
> :
> It would seem like there is a socket that is unregistered with the
> selector but is not successfully unregistered with the kernel. Am I right ?
>   
It's a complicated timing issue that arises when a SocketChannel is 
closed at just around the time that it gets registered with the polling 
facility. Closing is a two-step process, the first step involves dup the 
file descriptor to a special pre-close file descriptor that is connected 
to one end of a socket pair. To cut a long story short the socket pair 
ends up getting registered with the polling facility. When originally 
reported it took several weeks under heavy load to duplicate. The 
changes to fix it will be more extensive that originally expected so 
this is why the fix is not in jdk6. It is best to assume it will need to 
bake in jdk7 for a while before thinking about other releases.

-Alan.