Java を使用して複数のコマンド プロンプト コマンドを確実に実行するにはどうすればよいですか?

String command = "cmd /c start cmd.exe";
Process child = Runtime.getRuntime().exec(command);
OutputStream out = child.getOutputStream();
out.write("cd C:/ /r/n".getBytes());
out.flush();
out.write("dir /r/n".getBytes());
out.close();

String[] command = {"cmd"};
Process p = Runtime.getRuntime().exec(command);
new Thread(new SyncPipe(p.getErrorStream(), System.err)).start();
new Thread(new SyncPipe(p.getInputStream(), System.out)).start();
PrintWriter stdin = new PrintWriter(p.getOutputStream());
stdin.println("dir c:\ /A /Q");
stdin.close();
int returnCode = p.waitFor();
System.out.println("Return code = " + returnCode);

class SyncPipe implements Runnable {
  public SyncPipe(InputStream istrm, OutputStream ostrm) {
    istrm_ = istrm;
    ostrm_ = ostrm;
  }

  public void run() {
    try {
      final byte[] buffer = new byte[1024];
      for (int length = 0; (length = istrm_.read(buffer)) != -1; ) {
        ostrm_.write(buffer, 0, length);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private final OutputStream ostrm_;
  private final InputStream istrm_;
}