java how to know if a process is waiting for input
<p>I'm trying to create a process in java that starts a external file that asks for a number of arguments which the user gives at execution time.</p>

<p>The question is how to determine if the precess is asking for a argument </p>

<pre><code>    ProcessBuilder pb = new ProcessBuilder(c.fileName);
    Process proc = null;
    try {
        proc = pb.start();
    } catch (IOException ex) {
        Logger.getLogger(clas.class.getName()).log(Level.SEVERE, null, ex);
    }
    Scanner in = new Scanner(proc.getInputStream());
    PrintWriter out = null;
    out = new PrintWriter(proc.getOutputStream());
    while (in.hasNextLine()) {
        System.out.println(in.nextLine());
        out.println(1); // i don't want to give 1 untill the process need it ! 
        out.flush();
    }

    out.close();
</code></pre>
