Make a Text Field two columns wide in Java

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
/* ww w.  j  a  v a 2 s  . c  om*/
public class Main {
  public static void main(String[] args) {
    JTextField tf = new JTextField("mm");
    tf.setPreferredSize(tf.getPreferredSize());
    tf.setText("");

    JPanel pHacked = new JPanel();
    pHacked.add(tf);

    JPanel pStock = new JPanel();
    pStock.add(new JTextField(2));

    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLayout(new java.awt.GridLayout(0, 1));
    frame.add(pHacked);
    frame.add(pStock);
    frame.setSize(150, 150);
    frame.setVisible(true);
    tf.requestFocus();
  }
}