Runtime.exec and exitValue

Question

hi all,
i know about the miolion of topics about this object, but i've a question a little bit more specific.
I have a part of my code that needs to launch external command . I want to save the output of these commands, but i have to minimize the number of thread spawned. In addtion, i cannot know the number of command launched, so the thread number will became an important factor to bound.
At the same time i need to write something at the end of the output file, so i need to know when the process launched has terminated.
What i did:
//  main
//  here create a thread for process control
//   procControlThread
public void launchCommand(String cmd, String file, long ID){
  Process p  = Runtime.exec(cmd+" 1 >> "+file);
   procControlThread.addObj(p,file).
// in the procControlThread
public void addObj(Process p, String file){
     synchronized(struct){
          storeSomeWhere(p,file);
public void run(){
   Iterator i;
  while(boolean){
     synchronized(struct){
        i=struct.iterator();
         while(i.hasNext()){
            MyObj o = (MyObj)i.next();
             int exitCode;
              try{
                exitCode=o.getProcess().exitValue()
               }catch(IllegalThreadStateException e){
                      // process has not yet finished
                     continue;
                // process has finished
                // print in the file where is logged
               //  the stdout fo the command
                printSomething(o.getFile(),exitCode);
                 remove(o);
       Thread.sleep(10*1000);    
// where printSomething
// create  a Printwriter using a FileOutputStream.well, sometimes i get FileNotFoundException in the printSomething where is mentioned that the file is currently owned by another process.
do I miss something in the exit code?
I should using Process.WaitFor()? [ in this case I have to create one thread for controlling one process!]
-- jdk 1.3.1
Really thanks in advance.
T.

Answer 1

Seems like it should work. Obviously the code you posted is not the same as what you're running though (as it can't compile e.g. while (boolean)), so I'd wonder about what you're really doing.