I am kinda excited, this is the first new feature added to RXTX in 11 years! it also happens to fix a 15 year old bug, present in the library since USB to serial adapters were invented. The original developers never imagined the event of removing hardware, because back then Serial ports were built into the processor and could never be removed or added. This feature will now add a user level event when the hardware is removed. The user can then perform a shutdown procedure, since a connection will be needed after the hardware is removed. This also causes the Monitor thread that used to become a zombie to die properly.
testing for the change in Monitor thread