Question

I have a uint8 (unsigned 8 bit integer) coming in from a UDP packet. Java only uses signed primitives. How do I parse this data structure correctly with java?

Answer 1

Simply read it as as a byte and then convert to an int.

byte in = udppacket.getByte(0); // whatever goes here
int uint8 = in & 0xFF;

The bitmask is needed, because otherwise, values with bit 8 set to 1 will be converted to a negative int. Example:

This:                                   10000000
Will result in: 11111111111111111111111110000000

So when you afterwards apply the bitmask 0xFF to it, the leading 1’s are getting cancelled out. For your information: 0xFF == 0b11111111