import java.net.*; public class Lookup { public static void main(String[] args) { InetAddress addr = null; if (args.length!=1) { System.out.println("Syntax: java Lookup "); System.exit(1); } try { addr = InetAddress.getByName(args[0]); } catch(UnknownHostException e) { System.out.println("Unknown host name: "+args[0]); System.exit(1); } String hostname = addr.getHostName(); String address = addr.getHostAddress(); System.out.println("Host name: "+hostname); System.out.println("Internet address: "+address); } }