Using JRadioButton

// Creating radio buttons using ButtonGroup and JRadioButton.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class RadioButtonTest extends JFrame 
     {
     private JTextField t;
     private Font plainFont, boldFont,
     italicFont, boldItalicFont;
     private JRadioButton plain, bold, italic, boldItalic;
     private ButtonGroup radioGroup;
    
     public RadioButtonTest()
         {
         super( "RadioButton Test" );
        
         Container c = getContentPane();
         c.setLayout( new FlowLayout() );
        
         t = new JTextField( "Watch the font style change", 25 );
         c.add( t );
        
         // Create radio buttons
         plain = new JRadioButton( "Plain", true );
         c.add( plain );
         bold = new JRadioButton( "Bold", false);
         c.add( bold );
         italic = new JRadioButton( "Italic", false );
         c.add( italic );
         boldItalic = new JRadioButton( "Bold/Italic", false );
         c.add( boldItalic );
        
         // register events
         RadioButtonHandler handler = new RadioButtonHandler();
         plain.addItemListener( handler );
         bold.addItemListener( handler );
         italic.addItemListener( handler );
         boldItalic.addItemListener( handler );
        
         // create logical relationship between JRadioButtons
         radioGroup = new ButtonGroup();
         radioGroup.add( plain );
         radioGroup.add( bold );
         radioGroup.add( italic );
         radioGroup.add( boldItalic );
        
         plainFont = new Font( "TimesRoman", Font.PLAIN, 14 );
         boldFont = new Font( "TimesRoman", Font.BOLD, 14 );
         italicFont = new Font( "TimesRoman", Font.ITALIC, 14 );
         boldItalicFont = new Font( "TimesRoman", Font.BOLD + Font.ITALIC, 14 );
         t.setFont( plainFont );
         setSize( 300, 100 );
         show();
     }
    
     public static void main( String args[] )
         {
         RadioButtonTest app = new RadioButtonTest();
        
         app.addWindowListener( new WindowAdapter() 
             {
             public void windowClosing( WindowEvent e )
                 {
                 System.exit( 0 );
             }
         } );
     }
    
     private class RadioButtonHandler implements ItemListener 
         {
         public void itemStateChanged( ItemEvent e )
             {
             if ( e.getSource() == plain )
             t.setFont( plainFont );
             else if ( e.getSource() == bold )
             t.setFont( boldFont );
             else if ( e.getSource() == italic )
             t.setFont( italicFont );
             else if ( e.getSource() == boldItalic )
             t.setFont( boldItalicFont );
            
             t.repaint();
         }
     }
}