Short code snippet uses a lot of CPU. Suggestions on how to optimize?

Question

What I want to do is to ping a specified address after a specified delay, and then extract the delay and store it in a comma-separated file (optimally along with a timestamp). I could not find any way to make the delay with the ping command in windows XP, so I created a Timer for the task. The program does the trick, but the CPU usage jumps to about 50% when running the application. I'm kind of new to Java, and don't know all the do's and don'ts of threads and infinite loops. Any suggestion to how to optimize the code would be appreciated.
package WitelcomMonitor;
import java.io.*;
import java.util.Timer;
import java.util.TimerTask;
public class WitelcomMonitor {
     Timer timer = new Timer(true);
     int counter;
     public WitelcomMonitor(long delay){
          timer.schedule(new TaskPerformer(), 0, 5000);
     class TaskPerformer extends TimerTask{
          public void run(){
               try {
                    String line;
                    String[] command = {"ping", "-n","3", "123.12.12.1"};
                    Process p = Runtime.getRuntime().exec(command);
                    boolean append = true;
                    BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
                    PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("delayprofile.txt",append)));
                    String subline;
                    int indexEnd,indexStart;
                    while ((line = input.readLine()) != null) {
                         if(line.contains("TTL")){
                              counter++;
                              indexStart = indexEnd = line.indexOf("ms");
                              do {
                                   indexStart--;     
                              } while (line.charAt(indexStart)!='=');
                              subline = line.substring(indexStart+1,indexEnd);
                              out.print(subline.concat(","));
                              System.out.println(subline.concat(","));               
                         //System.out.println(counter);
                    input.close();
                    out.close();
               catch (Exception err) {
                    err.printStackTrace();
     public static void main(String[] args){
          long delay = 5000; //milliseconds     
          new WitelcomMonitor(delay);
          while(true);
}

Answer 1

Ok, so the while(true) statement by itself drains the CPU, while by asking the main thread to sleep in ten seconds intervals just to sleep again for ten seconds etc. will keep the load on the computer low. Yeah, it worked so I'm happy. I'm not sure though how I can avoid a new thread, as I have to extend TimerTask which requires that I override the run() method. This in turn causes a thread to be run in addition to the main thread. How do you suggest that I avoid this?