JAVA - JRadioButton - setting up Radio Button

A basic implementation of JRadioButton class for showing radio buttons to set text as italic , bold , plain or italic + bold 

Main class
import javax.swing.JFrame;

public class Main {
public static void main(String args[]) {

radioButton guiB = new radioButton();
guiB.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// set size and visibility of window
guiB.setSize(300, 100);
guiB.setVisible(true);

}


}


Radio button class

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.ButtonGroup;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JRadioButton;
import javax.swing.JTextField;

public class radioButton extends JFrame {
private JTextField tf;

//radio buttons for plain , bold , italic and italic+bold fonts 
private JRadioButton pR;  
private JRadioButton bR;    
private JRadioButton iR;  
private JRadioButton biR; 


private Font plain;
private Font bold;
private Font  italic;
private Font boldItalic;
//faamily of button group to relate with eachother , when any radio button is pressed
private ButtonGroup group;


// constructor
public radioButton(){
//title of window
super("radio button");

//set layout
setLayout(new FlowLayout());

//initialise text field
tf =  new JTextField("had a eve walk thru outskirts of village" , 25);
add(tf);

//initialise radio buttons 
//@params - string as label and boolean value to know if button is checked by default  
pR = new JRadioButton("plain" , true );  
bR = new JRadioButton("bold" , false  );
iR = new JRadioButton("italics" , false  );
biR = new JRadioButton("bold n italics" , false  );

//add buttons to window
add(pR); add(bR); add(iR); add(biR);


group = new ButtonGroup();
// add radio buttons to group
group.add(pR);
group.add(bR);
group.add(iR);
group.add(biR);

//initialise fonts
plain = new Font("Serif",Font.PLAIN , 30);
bold = new Font("Serif",Font.BOLD , 30);
italic = new Font("Serif",Font.ITALIC , 30);
boldItalic = new Font("Serif",Font.ITALIC + Font.BOLD , 30);

//set default font to textfield
tf.setFont(plain);

//add itemListener
//wait for event to happen and pass in  font object to constructor

pR.addItemListener(new HandlerClass(plain));
bR.addItemListener(new HandlerClass(bold));
iR.addItemListener(new HandlerClass(italic));
biR.addItemListener(new HandlerClass(boldItalic));

    }

private class HandlerClass implements ItemListener{

private Font font;

//sets the font to the font that was passed to contructor
@Override
public void itemStateChanged(ItemEvent e) {
tf.setFont(font);

}

public HandlerClass(Font f){
this.font  = f ;
}


}


}