import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.KeyEvent;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
public class Main {
public static void main(String args[]) {
JFrame f = new JFrame("LabelFor Sample");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container content = f.getContentPane();
JLabel label = new JLabel("Username");
JTextField textField = new JTextField();
label.setDisplayedMnemonic(KeyEvent.VK_U);
label.setLabelFor(textField);
Container box = Box.createHorizontalBox();
box.add(label);
box.add(textField);
content.add(box, BorderLayout.NORTH);
content.add(new JButton("Submit"), BorderLayout.SOUTH);
f.setSize(300, 200);
f.setVisible(true);
}
}