[JAVA] cannot find symbole

static InetAddress 	getByName(String host)
          Determines the IP address of a host, given the host's name.

package client_test;
import java.net.*;
//import java.lang.*; // ne peut pas être importé
import java.net.InetAddress;
import java.io.*; // pour les exceptions

/**
* @author Propriétaire
*/
class Com {

    public InetAddress adresse;
    public DatagramSocket socket;
    public DatagramPacket packet;
    public String requette, reponse;

    public Com(){}

    public void initCom(String str, int type){
        if(type == 0){
            try{
                adresse = InetAddress.getByName(str);
            }catch(UnknownHostException e){
                System.out.println(e.getMessage());
            }
        }
        try{
            socket = new DatagramSocket(11165);
        }catch(SocketException e){
            System.out.println(e.getMessage());
        }
    }

    public void sendCom(String str){
        requette = str;
        byte[] buffer = new byte[256];
        buffer = requette.getBytes();
        packet = new DatagramPacket(buffer,buffer.length,adresse,11165);
        try{
            socket.send(packet);
        }catch(IOException e){
            System.out.println(e.getMessage());
        }
    }

    public String recptCom(int type){
        byte[] buffer = new byte[256];
        packet = new DatagramPacket(buffer,buffer.length);
        try{
            socket.receive(packet);
        }catch(IOException e){
            System.out.println(e.getMessage());
        }
        if(type == 1)
            adresse = packet.getAddress();
        reponse = new String(packet.getData());
        return reponse;
    }

    public int cmpCom(String str1, String str2){
        if(str1.compareTo(str2) == 0){
            System.out.println(str2);
            return 0;
        }else{
            System.out.println("les deux chaines sont differentes");
            return -1;
        }
    }

    public void exitCom(){
        socket.close();
    }
}