Consider using nrjavaserial

[jvalkeal]

I was playing with samples and having a need to put native libs somewhere with -Djava.library.path is just so inconvenient. I quickly played with rxtx port in github.com/NeuronRobotics/nrjavaserial and it seem to work quite well and doesn't require to set library path manually.

Just switching those rxtx jars resulted MethodNotFoundException which is probably because current rxtx libs are so old on a byte level. I copied(without any modifications) SerialPortRxTx out from xbee sources order to compile against nrjavaserial and things worked well. I used copied SerialPortRxTx as a custom serial implementation.