rxtx and the BBB

Iḿ using the rxtx lib for sending / receiving some data at 19200 bps speed; the message rate is about 10 msg / sec, with a lenght of 10 bytes each.
After +/- 3 minutes the system still send the correct messages but in the input buffer only 1 byte is available.
Anybody knows if there an issue with rxtx lib and the BBB ?