7. Create checkboxes using swing

import java.awt.*;
import java.awt.event.*;
import java.util.logging.Handler;
import javax.swing.*;

public class Gui extends JFrame{

    // Variables
    private JTextField tf;
    private JCheckBox boldbox;
    private JCheckBox italicbox;

    // Constructor
    public Gui(){

        // Basics
        super("JFrame's title");
        setLayout(new FlowLayout());

        // Create the objects - variables
        tf = new JTextField("This is a sentence", 20);
        tf.setFont(new Font("Serif", Font.PLAIN, 14));
        add(tf);
        boldbox = new JCheckBox("Bold");
        italicbox = new JCheckBox("Italic");
        add(boldbox);
        add(italicbox);

        // Handler things in !!!! ItemListener !!!!
        HandlerClass handler = new HandlerClass();
        boldbox.addItemListener(handler);
        italicbox.addItemListener(handler);
    }

    private class HandlerClass implements ItemListener{
        public void itemStateChanged(ItemEvent event){
            Font font = null;
            if(boldbox.isSelected() && italicbox.isSelected()){
                font = new Font("Serif", Font.BOLD + Font.ITALIC, 14);
            }
            else if(boldbox.isSelected()){
                font = new Font("Serif", Font.BOLD , 14);
            }
            else if(italicbox.isSelected()){
                font = new Font("Serif", Font.ITALIC , 14);
            }
            else{
                font = new Font("Serif", Font.PLAIN , 14);
            }
            tf.setFont(font);
        }
    }

    // Main
    public static void main(String[] args){
        Gui gui = new Gui();
        gui.setDefaultCloseOperation(EXIT_ON_CLOSE);
        gui.setSize(600, 600);
        gui.setVisible(true);
    }
}