Sorry guys I've been out for few days and I couldn't reply here. Anyway:
PaulS:
int packetSize = Udp.parsePacket();
if (packetSize)
{
Serial.print("The incoming packet is ");
Serial.print(packetSize);
Serial.println(" bytes long");
packetSize isn't a boolean, and shouldn't be used like one. If you want to do something only when packetSize is greater than 0, make that explicit.
This is true, I didn't notice that "mistake" while copying the code prom the example.
I've used the Processing code here instead of MAX and the Arduino counts correctly the incoming bytes, it's weird how MAX is missing something. I need to check and see what's the problem there. However, I still need to understand how to receive bytes instead of char strings.
@SufferTim: I don't need to send non-string data, I need to READ non-string data on my Arduino. Anyway, the function you wrote down could be helpful. Thanks for your tips!