Temperature Conversion GUI Issue

Question

/*
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 * and open the template in the editor.
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package temperature.conversion;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.FlowLayout;
import javax.swing.JRadioButton;
import javax.swing.JButton;
import javax.swing.ButtonGroup;
import javax.swing.JTextField;
import javax.swing.JFrame;

import java.text.DecimalFormat;

/**
 *
 * @author Charles
 */
public class TemperatureConversion extends JFrame {

   private JTextField inputField;
   private JTextField outputField;
   private JRadioButton celstofahr;
   private JRadioButton fahrtocels;
   private JRadioButton celstokelv;
   private JRadioButton kelvtocels;
   private JRadioButton fahrtokelv;
   private JRadioButton kelvtofahr;
   private JButton converter;
   private ButtonGroup tempGroup;

   public TemperatureConversion() {
       super("Temperature Conversion Table");
       setLayout(new FlowLayout());

        celstofahr = new JRadioButton("Celsius to Fahrenheit", true);
       fahrtocels = new JRadioButton("Fahrenheit to Celsius", false);
       celstokelv = new JRadioButton("Celsius to Kelvin", false);
       kelvtocels = new JRadioButton("Kelvin to Celsius", false);
       fahrtokelv = new JRadioButton("Fahrenheit to Kelvin", false);
       kelvtofahr = new JRadioButton("Kelvin to Fahrenheit", false);

       add(celstofahr);
       add(fahrtocels);
       add(celstokelv);
       add(kelvtocels);
       add(fahrtokelv);
       add(kelvtofahr);

       tempGroup = new ButtonGroup();
       tempGroup.add(celstofahr);
       tempGroup.add(fahrtocels);
       tempGroup.add(celstokelv);
       tempGroup.add(kelvtocels);
       tempGroup.add(fahrtokelv);
       tempGroup.add(kelvtofahr); 

       inputField = new JTextField(" ", 4);
       inputField.addActionListener((ActionListener) this);
       converter = new JButton("Convert");
       converter.addActionListener(
         new ActionListener()
         {
    public void actionPerformed(ActionEvent event)
    {
        Object source = event.getSource();

      if(source ==  inputField) {
        double init_temp = 0.000;
        double final_temp = 0.00;
           DecimalFormat three = new DecimalFormat("0.000");

     String string_temp = inputField.getText();
     init_temp = Double.parseDouble(string_temp);

     if(celstofahr == source){
         final_temp = ((5/9) * init_temp) - 32;     
         outputField.setText(String.valueOf(final_temp));
     } 
     else if(fahrtocels == source){
         final_temp = ((1.8) * init_temp) + 32;
         outputField.setText(String.valueOf(final_temp));
     }
     else if(celstokelv == source){
         final_temp = init_temp + 273.16;    
         outputField.setText(String.valueOf(final_temp));
     }
     else if(kelvtocels == source){
         final_temp = init_temp - 273.16;    
         outputField.setText(String.valueOf(final_temp));
     }
     else if(fahrtokelv == source){
         final_temp = ((5/9) * (init_temp-32)) + 273.16; 
         outputField.setText(String.valueOf(final_temp));
     }
     else if(kelvtofahr != source){
     } else {
            final_temp = ((1.8) * (init_temp+32)) - 273.16;
            outputField.setText(String.valueOf(final_temp));
        }
     outputField.setText(" " + three.format(final_temp)); 
               }
             }
         }
      );
     add(converter);
   }
}

package temperature.conversion;

import javax.swing.JFrame;

/**
 *
 * @author Charles
 */
public class MainClass2 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        TemperatureConversion tempconversion = new TemperatureConversion();
        tempconversion.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        tempconversion.setSize(600, 600);
        tempconversion.setVisible(true);
    }
}

Here is the trouble:

run:
Exception in thread "main" java.lang.ClassCastException: temperature.conversion.TemperatureConversion cannot be cast to java.awt.event.ActionListener
    at temperature.conversion.TemperatureConversion.<init>(TemperatureConversion.java:61)
    at temperature.conversion.MainClass2.main(MainClass2.java:19)
Java Result: 1
BUILD SUCCESSFUL (total time: 3 seconds)

Answer 1

You used following lines, which does not make any sense

inputField.addActionListener((ActionListener) this);
         //This is the result of ClassCastException

But, you didn't implement ActionListener with JFrame. You should implement ActionListener with JFrame and overrride actionPerformed. You can listen specific action component using event.getSoruce to do specific work with action.