DatagramExample

DatagramExample -- sending and receiving datagram packets.

The DatagramExample class sets up a server socket that listens for datagrams. The partner DatagramClient class sends datagrams.

To see this example in action:

Compile the Java source file, DatagramExample.java:
```
	javac DatagramExample.java
```
Run the class on one machine:
```
	java DatagramExample
```
On a separate machine, or in a separate command line window, run the client class as a separate program. The final argument, if present, should name the machine on which your server process is running (the default value is the local host):
```
	java DatagramClient [server-host-machine]
```