```
InetAddress byName = Inet6Address.getByName(host);

```

Above code means, i want get the ip address by its name.

Then it runs successfully in the win2003 32bit OS,
but is catch UnknowHostException in the win2003 64bit OS.

So, I want to know "Is there any difference about the class java.net.InetAddress between 32bit OS and 64bit OS". 

The OS is different, so, the InetAddress in the jre/rt.jar package is different.