Java JTextField set preferred size based on font size

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.FontMetrics;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class Main extends JFrame {
  public Main() {
    super("JButton");

    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setLayout(new FlowLayout());
    JLabel nameLabel = new JLabel("Name:");
    JTextField name = new JTextField(20);
    name.setFont(new Font("Arial", Font.BOLD, 20));
    /*ww w  . j a v  a  2 s .c  o m*/
    FontMetrics fm = name.getFontMetrics(name.getFont());
    name.setPreferredSize(new Dimension(150, fm.getHeight()));

    getContentPane().add(nameLabel);
    getContentPane().add(name);

  }

  public static void main(String[] args) {
    Main frame = new Main();
    frame.pack();
    frame.setVisible(true);
  }
}