Network Packet Interpretation problem

Send a 3 character packet, Client Code Snip:
String alias = "Bob";
byte[] buf = alias.getBytes();
DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 4445);


Server Code Snip:
byte[] buf = new byte[256];
// receive request
DatagramPacket packet = new DatagramPacket(buf, buf.length);
incoming.receive(packet);
String received = new String(packet.getData());

The problem is that received (String) ends up containing "Bob" plus many characters of blank space. I just want valid characters in String received, which would be just "Bob" in this case. Should I add a character to indicate the end of the String? I'm hoping there is an easier, more efficient way.

Have you tried using getLength() on the incoming packet to limit the number of bytes copied out to the String?

Thanks a lot, that worked. I'm very new to networking in java.