applet报错
jsp和java代码如下：

JAVA:
import java.applet.Applet;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.Enumeration;
  
public class MACAddressApplet extends Applet  
{  
private static final long serialVersionUID = 6866002748735327341L;

public static String sep = ":";  
  public static String format = "%02X";  
   
  
  /**  
  * getMacAddress - return the first mac address found  
  * separator - byte seperator default ":"  
  * format - byte formatter default "%02X"  
  *  
  * @param ni - the network interface  
  * @return String - the mac address as a string  
  * @throws SocketException - pass it on  
  */  
  public static String macToString( NetworkInterface ni ) throws SocketException  
  {  
  return macToString( ni, MACAddressApplet.sep, MACAddressApplet.format );  
  }  
  
  /**  
  * getMacAddress - return the first mac address found  
  *  
  * @param ni - the network interface  
  * @param separator - byte seperator default ":"  
  * @param format - byte formatter default "%02X"  
  * @return String - the mac address as a string  
  * @throws SocketException - pass it on  
  */  
  public static String macToString( NetworkInterface ni, String separator, String format ) throws SocketException  
  {  
  byte mac [] = ni.getHardwareAddress();  
  
  if( mac != null ) {  
  StringBuffer macAddress = new StringBuffer( "" );  
  String sep = "";  
  for( byte o : mac ) {  
  macAddress.append( sep ).append( String.format( format, o ) );  
  sep = separator;  
  }  
  return macAddress.toString();  
  }  
  
  return null;  
  }  
  
  /**  
  * getMacAddress - return the first mac address found  
  *  
  * @return the mac address or undefined  
  */  
  public static String getMacAddress()  
  {  
  try {  
  Enumeration<NetworkInterface> nis = NetworkInterface.getNetworkInterfaces();  
  
  // not all interface will have a mace address for instance loopback on windows  
  while( nis.hasMoreElements() ) {  
  String mac = macToString( nis.nextElement() );  
  if( mac != null )  
  return mac;  
  }  
  } catch( SocketException ex ) {  
  System.err.println( "SocketException:: " + ex.getMessage() );  
  ex.printStackTrace();  
  } catch( Exception ex ) {  
  System.err.println( "Exception:: " + ex.getMessage() );