JTabbedPane and variable issue

Question

ok so here's what I've got, it's a mess I know, everything is added and defined and such, but got cut out to make the code fit, but before I can clean it up I have to figure out what is wrong, my problem as far as I can tell is I don't know how to reference variables in gui, I think I had this problem before but I don't know how to fix it, the variable names are right, it's looking in the right class but nothing in the tab can be found from the action listener. I don't know where else to look. I'm really hoping that's the issue anyway, and not something that requires the demolition of all the code. thank you,
import java.awt.*;
import javax.swing.*;
import java.util.*;
import java.text.*;
import java.awt.event.*;
import java.io.*;
public class PoolEstimator extends JFrame
public PoolEstimator()
super( "Pool Estimator" );
DefaultListModel listModel = new DefaultListModel();
JTabbedPane tab = new JTabbedPane();
// constructing the second panel
JPanel CustInfo = new JPanel();
CustInfo.setLayout(new FlowLayout(FlowLayout.LEFT));
JLabel FirstName, LastName, Street, City, Zip, Phone, poolDepthup, poolDepthlow,
yardLength, poolLength, yardWidth, poolWidth, state;
JTextField FirstNamein, LastNamein, Streetin, Cityin, Zipin,
Phonein, poolDepthupin, poolDepthlowin, yardLengthin, poolLengthin, yardWidthin, poolWidthin;
String[] States = {"AL","AK","AS","AZ","AR","CA","CO","CT","DE","DC","FL","GA","HI","ID","IL","IN","IA",
"KS","KY","LA","ME","MD","MA","MI","MN","MS","MO","MT","NE","NV","NH","NJ","NM","NY","NC","ND","OH","OK",
"OR","PA","RI","SC","SD","TN","TX","UT","VT","VA","WA","WV","WI","WY"};
JComboBox State = new JComboBox(States);
FirstName = new JLabel("First Name");
LastName = new JLabel("Last Name");
Street = new JLabel("Street Address");
City = new JLabel("City");
state = new JLabel("State");
Zip = new JLabel("Zip Code");
Phone = new JLabel("Phone Number");
yardLength = new JLabel("Length of the yard.");
yardWidth = new JLabel("Width of the yard.");
poolDepthup = new JLabel("Deepest depth of the pool.");
poolDepthlow = new JLabel("Shalowest depth of the pool.");
poolLength = new JLabel("Length of the pool.");
poolWidth = new JLabel("Width of the pool.");
FirstNamein  = new JTextField(20);
LastNamein   = new JTextField(20);
Streetin   = new JTextField(25);
Cityin   = new JTextField(15);
Zipin  = new JTextField(5);
Phonein  = new JTextField(5);
poolDepthupin  = new JTextField(2);
poolDepthlowin  = new JTextField(2);
yardLengthin  = new JTextField(3);
poolLengthin  = new JTextField(3);
yardWidthin  = new JTextField(3);
poolWidthin  = new JTextField(3);
JButton Add = new JButton("Add");
CustInfo.add(Add);
tab.addTab( "New Customer Estimate", null, CustInfo, "Customer Information Page" );
getContentPane().add( tab );
setSize( 325,400 );
setVisible( true );
addWindowListener(new WindowAdapter()
   public void windowClosing(WindowEvent e)
   System.exit(0);
     AddButtonHandler AddNew = new AddButtonHandler();
     Add.addActionListener(AddNew);
class AddButtonHandler implements ActionListener
     public void actionPerformed(ActionEvent e)
          try
          //PoolEstimator run  = new PoolEstimator();
          String StateSelection = PoolEstimator.State.getSelectedItem().toString();
          FileWriter AddEstimate = new FileWriter("Estimate.dat", true);
          AddEstimate.write("First Name: ");
          //AddEstimate.write(run.FirstNamein.getText());
          AddEstimate.write("\nLast Name:  ");
          //AddEstimate.write(LastNamein.getText());
          AddEstimate.write("\nTotal Cost:  ");
          //int width, length, depthupper, depthlower, SurfaceArea, Cement, Rebar, Labor, totalCost;
          //width =Integer.parseInt(poolWidthin);
          //length = Integer.parseInt(poolLengthin);
          //depth = (Integer.parseInt(poolDepthupin) + Integer.parseInt(poolDepthlowin))/2;
          //SurfaceArea = (width * depth)*2+(length*depth)*2;
          //Cement = SurfaceArea * 3;
          //Rebar = SurfaceArea *5;
          //Labor = SurfaceArea%10*18;
          //totalCost = Cement+Rebar+Labor;
          //AddEstimate.write(totalCost);
          AddEstimate.write("\n,");
          AddEstimate.close();
          //run.listmodel.add(run.FirstNamein + run.LastNamein);
        catch(IOException r)
        JOptionPane.showMessageDialog(null,r.getMessage(),"ERROR",2);
public static void main( String args[] )
PoolEstimator run = new PoolEstimator();
run.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
}

Answer 1

Im a newbie but Im finding it hard to understand what your talking about.
Could you explain what your program is suppose to do and what you want it to do that it isnt doing yet because you dont know how?
Plus I just thought I would mention this incase but its easier to use the following JFrame method instead of adding a window adaptor:
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);