iosample example not working

when running the iosample example from XBee Java Libray, I don’t get the printing message in the console :
System.out.println("New sample received from " + remoteDevice.get64BitAddress() + " - " + ioSample);
I have checked that the remote xbee is sending correct packets via xctung.
Does anyone have an idea to have the java program working ?
Thank you