Issue using Runtime.exec() in Vista

Question

I've coded a simple method using Runtime.exec() to get the client MAC ID , and it worked alright on XP. Now my client want to switch to vista , and the method is not working. Here's my code
import java.io.*;
import java.util.regex.*;
public class GetMac
     public static String getMacAddress()
          String mac="";
          System.out.println("getMacAddress");
          try {
               RunTimeExecutor re=new RunTimeExecutor("ipconfig /all");
                mac=re.executeAndReturnMac();
                re.destroy();
          } catch (Exception e) {
               e.printStackTrace();
          return mac;
import java.io.IOException;
import java.io.InputStream;
* @author amal
public class RunTimeExecutor
          String cmd;
          Process proc;
           * @param cmd
          public RunTimeExecutor(String cmd)
                    this.cmd=cmd;
           * @return boolean
           * @throws WIException
          public  String executeAndReturnMac() throws Exception
               System.out.println("run");
               String mac="";
                    if(cmd==null)
                              throw new Exception("No Commands");
                    try
                          final Runtime rt = Runtime.getRuntime();
                          proc = rt.exec(cmd);
                          final StreamGobbler errorGobbler = new StreamGobbler(proc.getErrorStream());
                          InputStream iis=proc.getInputStream();
                          final StreamGobbler outputGobbler = new StreamGobbler(iis);
                          errorGobbler.start();
                          outputGobbler.start();
                          int exit=proc.waitFor();
                          System.out.println("exitVAl "+exit);
                          if(exit==0)
                               mac=outputGobbler.MAC;
                          return (exit==0) ? mac :null;
                catch (IOException e)
                          e.printStackTrace();
                catch (InterruptedException e)
                          e.printStackTrace();
                catch(Exception e)
                     e.printStackTrace();
                return null;
          public void destroy()
                    if(proc!=null )
                              proc.destroy();
* @author amal
import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
* @author amal
public class StreamGobbler extends Thread
    InputStream is;
    OutputStream os;
    public String MAC;
    StreamGobbler(InputStream is)
        this(is,null);
    StreamGobbler(InputStream is,OutputStream redirectTo)
        this.is = is;
        this.os = redirectTo;
     * @see java.lang.Thread#run()
    public void run()
        try
            PrintWriter pw = null;
            if (os != null)
                pw = new PrintWriter(os);
            InputStreamReader isr = new InputStreamReader(is);
            int c=0;
            BufferedReader br = new BufferedReader(isr);
            String line=null;
System.out.println("Start Reading");
                 while ( (line = br.readLine()) != null)
                      System.out.println(line);
                     if (pw != null)
                         pw.println(line);
                     Pattern p = Pattern.compile(".*Physical Address.*: (.*)");
                        Matcher m = p.matcher(line);
                        if (m.matches())
                             MAC = m.group(1);
                             System.out.println("seting MAC to "+MAC);
                             break;
            if (pw != null)
                pw.flush();
        } catch (Exception e)
            e.printStackTrace(); 
}The inputStream of the process doesnt get printed at all , the loop condition in StreamGobbler 'while ( (line = br.readLine()) != null)
' is never true.
Also , in random cases i've seen the System.out.println("exitVAl "+exit); line executing before the System.out.println("Start Reading"); line , and i though proc.waitFor() would guarentee otherwise.

Answer 1

thx guys for ur replies . The issue was because of some browser security system ( or so they said . ).However i'm still puzzled about the 'waiting for the stream to finish' part .
paul.miner wrote:
{I think the process is allowed to end with output still in the >>buffers, ..so this would be expected. You should be waiting for >>your .streams to finish, since that's what you really >>care .about. .Also, .you need to add synchronization between your >>threads so you can accurately retrieve "MAC". Also, do not break out >>of the loop when you find what you're looking for, you should >>continue .reading until the end of the stream.Wasn't I suppose to be reading out of the stream to prevent an overflow?Also the break is done there are multiple lines like 'Physical address .....: xxxxxxxxxx ' in the output , and the macid is the first one.About the ProcessBuilder , I'll look into it . Thx for your advice.