# VBForums CodeBank > CodeBank - Java / J# >  Java - Host Lookup

## Dillinger4

_nslookup_ is a Unix utility that converts hostnames to IP addresses and IP addresses to hostnames. The following program emulates _nslookup_ without any of _nslookup's_ complex features.


```
 import java.io.*; 
 import java.net.*; 

 public class AddressResolver{
  public static void main(String[] args){
    AddressResolver.prompt(); 
    BufferedReader buff = new BufferedReader(
      new InputStreamReader(System.in)
   ); 
  String address = null;
 for(;;){
  try{
    address = buff.readLine(); 
  }catch(IOException io){System.err.println(io);}
   if(address.equals("e")){
      System.out.println("Thank you for using AddressResolver"); 
      break; 
   }
  InetAddress ina = null; 
  try{
   ina = InetAddress.getByName(address); 
  }catch(UnknownHostException uhe){System.out.println(address + " is not a valid host");
    AddressResolver.prompt(); 
    continue; 
   }
   if(address.endsWith(".com")){
    System.out.println(address + " resolves to " + ina.getHostAddress());
     AddressResolver.prompt(); 
   }else{
   System.out.println(address + " resolves to " + ina.getCanonicalHostName());
    AddressResolver.prompt(); 
   }
  }
 }
 private static void prompt(){
    System.out.println();
    System.out.println("Please enter an ip address or a url"); 
    System.out.println("Press e to exit"); 
    System.out.println();
 }
}
```

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