🚀 go-pugleaf

Dear Colleague,
  I am trying to run a subprocess in a different thread. 
in the parent process, I want to show the user the progress information
about the subprocess. But what happend is that, All the messages come out
in a buffered fashion. it is not line by line. messages come out block by
block. Does anybody knows the solutions to it?
The following is code fragmenent in the subprocess class
it is reside in the run() method.
      String msg;
      Process proc = Runtime.getRuntime().exec(cmd);
      InputStreamReader isr =  new InputStreamReader(proc.getInputStream
()) ;
      BufferedReader bf = new BufferedReader(isr);
      InputStreamReader err = new InputStreamReader(proc.getErrorStream ())
;
      BufferedReader bferr = new BufferedReader(err);
      while ( (msg = bf.readLine()) != null) {
        fireActionPerformed(new ActionEvent(this,
ActionEvent.ACTION_PERFORMED, msg));
      }