🚀 go-pugleaf

I want to capture the standard output of a console program written in C in a
JTextArea component.  The code I am running is shown below.  The issue I
have is:  it takes inordinately long for the the first line of    output to
appear; and when it does all of the ouput (about 20 lines) appears together.
This is not the case if I run the program from the DOS prompt.  Any ideas
why the behavior is different when the program is run under control of a
Java program?

     cycleProcess = rt.exec(command, null, currentDir);
        InputStreamReader isr = new
InputStreamReader(cycleProcess.getInputStream());
        batchLogReader = new LineNumberReader(isr);
        outputLine = batchLogReader.readLine();
        while (outputLine  != null) {
          outputLine = batchLogReader.readLine();
          messagesTextArea.setText(messagesTextArea.getText() + "\n" +
outputLine);
          messagesTextArea.paintImmediately(messagesTextArea.getBounds());
        }