Exception in thread "SocketThread" java.lang.IllegalArgumentException: 0 > -257

I get the following error:

Exception in thread "SocketThread" java.lang.IllegalArgumentException: 0 > -257































at java.util.Arrays.copyOfRange(Arrays.java:3513)































at com.guarddoggps.main.SocketThread.run(SocketThread .java:39)

I have an array of unsigned chars in c sent over udp socket to java. It looks something like the following (although I changed the array contents a little here):

Java Code:

unsigned char msg[] = {0x28, 0xC2, 0x43, 0x80, 0x0, 0x0, 0xD};

Now in Java I want to extract this portion of the array:

0x28, 0xC2, 0x43, 0x80, 0x0, 0x0

So I come up with this:

Java Code:

              byte[] buf = new byte[256];
              DatagramPacket packet = new DatagramPacket(buf, buf.length);
              socket.receive(packet);
              
              byte[] resp = packet.getData();              
              int delimiter = Arrays.binarySearch(resp, (byte)0xD);
                            
              byte[] data = Arrays.copyOfRange(resp, 0, delimiter);

But it thinks the delimiter is out of range from resp byte array. I have no idea where this -257 comes from.