[Rxtx] port in use exception

[Gregg Wonderly]

Dr. Douglas Lyon wrote:
> Trent Jarvi Said:
>>Perhaps you are trying to open the port before the kernel is ready?  Are
>>you opening right after closing?  The more recent versions of rxtx may
>>close the port faster which could make a difference depending how you are
>>using threads.

An API shouldn't make a synchronous event, such as freeing a resource, into an 
ansynchrous activity unless it can also mediate a rendevous of any future users 
of such a resource.  The normal use of open and close on resources in an 
operating system is synchronous.  I think it's really not a good idea to make 
the close asynchronous.  Some might do this to keep the application from waiting 
for a flush on a slow connection, or one with stuck flow control.  It really 
should block the caller until the close completes, and let the calling 
environment decide that their application requires asynchronous behavior.

Gregg Wonderly