Applet is not working and I do not know why it is not working

Question

I cannot figure out why my applet is not working. Can someone assist me with this problem?
Here is the code:
As you will soon find out some of those imports can be ignored.
import java.lang.Integer;
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.awt.event.ItemListener;
import java.awt.event.ItemEvent;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.*;
import java.awt.Graphics.*;
import javax.swing.*;
import java.awt.*;
import javax.swing.text.*;
import javax.swing.event.*;
import java.awt.event.*;
import javax.swing.JApplet.*;
import javax.swing.JFrame.*;
import java.applet.Applet;
import javax.swing.border.*;
import javax.swing.Spring.*;
import java.awt.geom.AffineTransform;
import java.awt.Graphics2D;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;
import java.math.*;
public class Test extends JApplet{
JFormattedTextField Relfield;
JFormattedTextField Relfield2;
JFormattedTextField Relfield3;
GridLayout layout = new GridLayout();
public void init() {
Double d = 0.0;
Double e = 0.0;
Relfield2 = new JFormattedTextField();
Relfield3 = new JFormattedTextField();
Relfield = new JFormattedTextField();
Relfield.setText(d + "");
Relfield2.setText(e + "");
TextFieldHandler handlers = new TextFieldHandler();
Relfield.addPropertyChangeListener(handlers);
JButton button1 = new JButton("1");
JButton button2 = new JButton("2");
button1.addActionListener(new T5C());
button2.addActionListener(new T6C());
Container c = getContentPane();
c.setLayout(layout);
c.add(Relfield);
c.add(Relfield2);
c.add(button1);
c.add(button2);
class T5C implements ActionListener
public void actionPerformed(ActionEvent e) {
Double b = (Double)(Double.parseDouble(Relfield.getText())) + 1;
Relfield.setValue(b + "");
Relfield2.setValue(b + "");
class T6C implements ActionListener
public void actionPerformed(ActionEvent e) {
Double b = (Double)(Double.parseDouble(Relfield.getText())) - 1;
Relfield.setValue(b + "");
Relfield2.setValue(b + "");
public class TextFieldHandler implements PropertyChangeListener {
public void propertyChange(PropertyChangeEvent e) {
Object source = e.getSource();
if (source == Relfield) {
Double Rel = ((Double)Relfield.getValue()).doubleValue();
Relfield.setValue(Rel);
Relfield2.setValue(Rel);
//BigDecimal myu = new BigDecimal("Relfield.getValue()");
public static void main( String[] argv ) {
        JFrame frame = new JFrame( "General Shear Mode Damper Design" );
        frame.addWindowListener( new WindowAdapter(){
            public void windowClosing( WindowEvent e ){
                System.exit( 0 );
        JApplet applet = new Test();
        frame.getContentPane().add(applet);
        applet.init();
        frame.setSize( 1020, 720);
        frame.setVisible(true);
}

Answer 1

The applet is not running at all and I can't figure out the error messages.
The error messages are below:
C:\Users\zite.1\Desktop>javac Test.java
C:\Users\zite.1\Desktop>java Test
Exception in thread "main" java.lang.NullPointerException
at Test$TextFieldHandler.propertyChange(Test.java:89)
at java.beans.PropertyChangeSupport.firePropertyChange(Unknown Source)
at java.beans.PropertyChangeSupport.firePropertyChange(Unknown Source)
at java.awt.Component.firePropertyChange(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at javax.swing.JRootPane.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at java.awt.Panel.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at javax.swing.JComponent.addNotify(Unknown Source)
at javax.swing.JRootPane.addNotify(Unknown Source)
at java.awt.Container.addNotify(Unknown Source)
at java.awt.Window.addNotify(Unknown Source)
at java.awt.Frame.addNotify(Unknown Source)
at java.awt.Window.show(Unknown Source)
at java.awt.Component.show(Unknown Source)
at java.awt.Component.setVisible(Unknown Source)
at java.awt.Window.setVisible(Unknown Source)
at Test.main(Test.java:112)