Swing JLabel text change on the running application

Question

I have a Swing window which contains a button a text box and a JLabel named as flag. According to the input after I click the button, the label should change from flag to some value.

How to achieve this in the same window?

Answer 1

import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
public class Test extends JFrame implements ActionListener
{
    private JLabel label;
    private JTextField field;
    public Test()
    {
        super("The title");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setPreferredSize(new Dimension(400, 90));
        ((JPanel) getContentPane()).setBorder(new EmptyBorder(13, 13, 13, 13) );
        setLayout(new FlowLayout());
        JButton btn = new JButton("Change");
        btn.setActionCommand("myButton");
        btn.addActionListener(this);
        label = new JLabel("flag");
        field = new JTextField(5);
        add(field);
        add(btn);
        add(label);
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
        setResizable(false);
    }
    public void actionPerformed(ActionEvent e)
    {
        if(e.getActionCommand().equals("myButton"))
        {
            label.setText(field.getText());
        }
    }
    public static void main(String[] args)
    {
        new Test();
    }
}