Runtime.getRuntime().exec question

Question

Hi
I have written an program where i need to open files on my computer with specific commands, but it wont work correctly.
It looks something like this in my Tools class:
public void setCustomCmd (String cmd) {
          customOpenCmd = cmd;
     public void openCustom (String[] path) {          
          String[] uu = new String[path.length + 1];
          uu[0] = customOpenCmd;
          for (int i = 1;i < uu.length;i++) {
               uu[i] = path[i - 1];
          try {
               Process p = Runtime.getRuntime().exec(uu);
          } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
     }I am trying to open an array of files with the specified command, like some movies with gmplayer. (im using linux, but it would be good to make this method platform independent). The thing is it "kind of" works. When i give an array with paths to smplayer (an frontend for mplayer) they will be added to the playlist and i can play the movies, but smplayer behaves strange. When i try to open the settings or the file info for instance, smplayer just freezes. Gmplayer also "kind of" works, until i try to close it. It will freeze and i have to kill the process. (in both cases the movie still plays, but the frontend for mplayer itself freezes).
So far i have been able to solve every problem in my learning process of java (and programming in general) with google, but im just unable to make any progress with this problem (and i REALLY have tried everything i can think of). So, can anyone help me?
Also, smplayer does write some output to the terminal when i run it, do i need to handle that from java somehow as well?
Thanks in advice.

Answer 1

Hah! now i managed to make it work perfectly. Here is my code (maybe its a bit ugly since I'm quite new to programming in general, but it may help someone who tries to accomplish the same thing):
public void setCustomCmd (String cmd) {
          customOpenCmd = cmd;
     public void openCustom (String[] path) {          
          String[] uu = new String[path.length + 1];
          uu[0] = customOpenCmd;
          for (int i = 1;i < uu.length;i++) {
               uu[i] = path[i - 1];
          RunCmd zzz = new RunCmd(uu);
          zzz.start();
     private class RunCmd extends Thread
         Process proc;
         String[] cmd;
         RunCmd(String[] cmdIn)
            cmd = cmdIn;
         public String[] getCmd() {
              return cmd;
         public boolean setCmd(String[] cmdIn) {
              // Don't change the command in case this thread is alive.
              if (this.isAlive()) {
                   return false;
              cmd = cmdIn;
              return true;
         public void run()
              try
                   // Execute the command in run to avoid problems in case someone forgets to call
                   // run and the process "kind of" works as an result.
                   Runtime rt = Runtime.getRuntime();
                   proc = rt.exec(cmd);
                 // any error message?
                 StreamGobbler errorGobbler = new
                     StreamGobbler(proc.getErrorStream(), "ERR");           
                 // any output?
                 StreamGobbler outputGobbler = new
                     StreamGobbler(proc.getInputStream(), "OUT");
                 // kick them off
                 errorGobbler.start();
                 outputGobbler.start();
                 // any error???
                 int exitVal = proc.waitFor();
                 log.print(customOpenCmd + ":<BR>" + "<font color=green>ExitValue: " + exitVal + "</font color=green>");
                 log.print("");
             } catch (Throwable t)
                 t.printStackTrace();
     private class StreamGobbler extends Thread
         InputStream is;
         String type;
         OutputStream os;
         StreamGobbler(InputStream is, String type)
             this(is, type, null);
         StreamGobbler(InputStream is, String type, OutputStream redirect)
             this.is = is;
             this.type = type;
             this.os = redirect;
         public void run()
             try
                 PrintWriter pw = null;
                 if (os != null)
                     pw = new PrintWriter(os);
                 InputStreamReader isr = new InputStreamReader(is);
                 BufferedReader br = new BufferedReader(isr);
                 String line=null;
                 while ( (line = br.readLine()) != null)
                     if (pw != null)
                         pw.println(line);
                     System.out.println(customOpenCmd + ": " + type + ">" + line);
                     // log.printNoTime(customOpenCmd + ": " + type + ">" + line); So much output, my log is 2 slow :p
                 if (pw != null)
                     pw.flush();
             } catch (IOException ioe)
                 ioe.printStackTrace(); 
     }This executes the command and lets the program continue even if the execition still runs. I have only tried this a few times, so if i encounter problems with this code i will post the solution if i manage to find it.