hi all i am making a weather data program and i having a problem for bringinng my text file to the table. here i am putting all my code . and i also have to import a second output window for my code. for example when ever i enter ome value int he window to compute it should show that value in the other window after compute. i have that code ready but i dont know how to implement in this one.

    package windchill;

import java.awt.Color;
import java.awt.Desktop.Action;
import java.awt.Font;
import java.awt.Toolkit;                          
import java.awt.event.*;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.Scanner;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;import java.awt.BorderLayout;
import java.awt.FlowLayout;   
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.table.DefaultTableModel;

import javax.swing.JFileChooser;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class GUI extends JFrame implements ActionListener {

/**
 * 
 */
private static final long serialVersionUID = 1L;
JLabel label1, label2, label3, label4;
JTextField t1, t2, t3;
JButton fileButton, computeButton, cancelButton;

public GUI() { 

    setLayout(null);
    setSize(500, 500);

setTitle(" Weather Project");

    label1 = new JLabel("Wind Chill Factor");
    label1.setBounds(50, 30, 150, 30);
    label2 = new JLabel("Enter The Temperature In Degrees (Fahreheit)");
    label2.setBounds(30, 100, 270, 30);
    label3 = new JLabel("Enter The Wind Speed In (mph)");
    label3.setBounds(30, 200, 200, 30);
    label4 = new JLabel("Enter The Dew Point In Degrees (Fahreheit)");
    label4.setBounds(30, 300, 250, 30);
    t1 = new JTextField();
    t1.setBounds(300, 100, 120, 30);
    t2 = new JTextField();
    t2.setBounds(300, 200, 120, 30);
    t3 = new JTextField();
    t3.setBounds(300, 300, 120, 30);
    fileButton = new JButton("File Entry");
    fileButton.setBackground(Color.ORANGE);
    fileButton.setBounds(30, 380, 120, 30);
    computeButton = new JButton("Compute");
    computeButton.setBackground(Color.ORANGE);
    computeButton.setBounds(300, 380, 120, 30);
    cancelButton = new JButton("Cancel");
    cancelButton.setBackground(Color.ORANGE);
    cancelButton.setBounds(300, 380, 120, 30);

    add(label1);
    add(label2);
    add(label3);
    add(label4);
    add(t1);
    add(t2);
    add(t3);
    add(fileButton);
    add(computeButton);
    add(cancelButton);

    t1.addKeyListener(new KeyAdapter() {
        public void keyTyped(KeyEvent ke) {
            char c = ke.getKeyChar();
            if (!(Character.isDigit(c))) {
                ke.consume();
            }
        }
    });

    t2.addKeyListener(new KeyAdapter() {
        public void keyTyped(KeyEvent ke) {
            char c = ke.getKeyChar();
            if (!(Character.isDigit(c))) {
                ke.consume();
            }
        }
    });

    t3.addKeyListener(new KeyAdapter() {
        public void keyTyped(KeyEvent ke) {
            char c = ke.getKeyChar();
            if (!(Character.isDigit(c))) {
                ke.consume();
            }
        }
    });

    fileButton.addActionListener(this);
    computeButton.addActionListener(this);
    cancelButton.addActionListener(this);

}

// Action listener on Choose File
public void actionPerformed(ActionEvent ae) {                                   

    if (ae.getSource() == fileButton) {

        FileChooser fc = new FileChooser();
        String data[][] = fc.get();

        ListShow listShow = new ListShow();
        listShow.showFunc(data);

    }

//Action listener on Compute Button
        if (ae.getSource() == computeButton) {                                       
            try {
                if ((t1.getText().equals("")) || (t2.getText().equals(""))
                        || (t3.getText().equals(""))) {
                    JOptionPane.showMessageDialog(null,
                            "Fields Cannot Be Empty");
                } 

            double temp = Double.parseDouble(t1.getText());
            double speed = Double.parseDouble(t2.getText());
            double dew = Double.parseDouble(t3.getText());

            if (temp <= 50 && speed >= 3) {
                WindChill wc = new WindChill(temp, speed, dew);
                wc.setVisible(true);
            } else {
                JOptionPane.showMessageDialog(null,
                        "An Invalid Value Has Been Entered");
            }
        } catch (Exception e) {
            System.out.println("Fields Cannot Be Empty");
        }
    }
    }

    public static void main(String[] args) {
    GUI g1 = new GUI();
    g1.setVisible(true);
    g1.setIconImage(Toolkit.getDefaultToolkit().getImage("Users\\mihirpatel8138\\Desktop\\weather.png"));
}
    public class WindChill extends JFrame implements ActionListener {

        /**
         * 
         */
        private static final long serialVersionUID = 1L;
        JLabel l1, l2, l3;
        JButton windChillButton, cloudBaseButton, showDataInTable;
        JTextField t1, t2, t3, t4, t5;
        int temp, speed, dew;
        private String p1;

        public WindChill(double temp2, double speed2, double dew2) {                        

            setLayout(null);
            setSize(550, 550);
            l1 = new JLabel("Temperature in Farenhiet is: ");
            l1.setBounds(30, 100, 270, 30);
            t1 = new JTextField("" + temp2);
            t1.setBounds(300, 100, 120, 30);
            l2 = new JLabel("Speed in mph is: ");
            l2.setBounds(30, 200, 200, 30);
            t2 = new JTextField("" + speed2);
            t2.setBounds(300, 200, 120, 30);
            l3 = new JLabel("Dew is: ");

            l3.setBounds(30, 300, 250, 30);
            t3 = new JTextField("" + dew2);
            t3.setBounds(300, 300, 120, 30);
            windChillButton = new JButton("Calculate Wind Chill Factor");
            windChillButton.setBackground(Color.ORANGE);
            windChillButton.setBounds(30,350,150,30);
            cloudBaseButton = new JButton("Calculate Cloud Base Altitude");
            cloudBaseButton.setBackground(Color.ORANGE);
            cloudBaseButton.setBounds(30, 400,150,30);
            showDataInTable = new JButton("Save Values to Table");
            showDataInTable.setBounds(100, 450, 300, 30);

            t4 = new JTextField(20);
            t4.setBounds(300, 350, 120, 30);
            t5 = new JTextField(20);
            t5.setBounds(300, 400, 120, 30);

            t1.setEditable(false);
            t2.setEditable(false);
            t3.setEditable(false);
            t4.setEditable(false);
            t5.setEditable(false);

            add(l1);
            add(t1);
            add(l2);
            add(t2);
            add(l3);
            add(t3);
            add(windChillButton);
            add(cloudBaseButton);
            add(t4);
            add(t5);
            add(showDataInTable);

            windChillButton.addActionListener(this);
            cloudBaseButton.addActionListener(this);
            showDataInTable.addActionListener(this);
        }

        public void actionPerformed(ActionEvent e) {

            double temp = Double.parseDouble(t1.getText());
            double speed = Double.parseDouble(t2.getText());
            double dew = Double.parseDouble(t3.getText());

            if (e.getSource() == windChillButton) {

                double windChill = 35.74 + (.6215 * temp) - (35.75 * (Math.pow(speed, 0.16))) + .4275 * temp * (Math.pow(speed, 0.16));                             // Minified formula to calculate windChill 

                String s = String.format("%.2f", windChill);
                System.out.println(s);

                t4.setText(s);
            }

            if (e.getSource() == cloudBaseButton) {

                double cloudbase = (temp - dew) / 4.4 * 1000;
                String s1 = String.format("%.2f", cloudbase);
                System.out.printf("%.2f",cloudbase);
                t5.setText(s1);

            }

                if (e.getSource() == showDataInTable) 

            {
                String p2, p3, p4, p5;
                p1 = t1.getText();
            p2 = t2.getText();
            p3 = t3.getText();
            p4 = t4.getText();
            p5 = t5.getText();
            ListShow l1 = new ListShow();
            l1.setVisible(true);

        }
        }
    }

    public static class FileChooser extends JFrame  {

        /**
         * 
         */
        private static final long serialVersionUID = 1L;
        JFileChooser JFileChooser;
        int j;
        String a1 = "";

        static int countLine=0;
        private BufferedReader br;

        String[][] get() {

            String[][] data = new String[50][];

            JFileChooser fileChooser = new JFileChooser();
            fileChooser.setCurrentDirectory(new File(System.getProperty("user.home")));
            int result = fileChooser.showOpenDialog(this);
            File selectedFile = null;
            if (result == javax.swing.JFileChooser.APPROVE_OPTION) {

                selectedFile = fileChooser.getSelectedFile();
                System.out.println("Selected file: " + selectedFile.getAbsolutePath());
            }

            try {
                String s1 = selectedFile.getAbsolutePath();
                FileReader fr = new FileReader(s1);         // Reading of file
                        br = new BufferedReader(fr);
                        String line = br.readLine();

                        int j = 0;
                        while (line != null && !line.isEmpty()) {
                            data[j] = line.split("-");
                            j++;
                            line = br.readLine();
                            countLine++;
                        }
            }catch (Exception e) {          

                System.out.println("No file has been choosen");
            }
            return data;
        }

    }

public class ListShow extends JFrame {

        private static final long serialVersionUID = 1L;
        DefaultTableModel model = null;
        JFrame screen = new JFrame("Calculation Table");
        JPanel pnl = new JPanel();

        ListShow() {                                    // Constructor of ListShow class 
            String h[] = { "Temperature", "Speed", "Dew Point",
                    "Wind Chill Factor", "Cloud Base Altitude" };
            model = new DefaultTableModel(h, 0);
        }
        void showFunc(String[][] data) {                // function to show the data in the Table 
            setLayout(new FlowLayout());
            setSize(100, 500);

            for (int i = 0; i < 0; i++) {
                double temp = Double.parseDouble(data[i][0]);
                double speed = Double.parseDouble(data[i][1]);
                double dew = Double.parseDouble(data[i][2]);

                double chillFactor = 35.74 + (.6215 * temp) - (35.75 * (Math.pow(speed, 0.16))) + .4275 * temp * (Math.pow(speed, 0.16));

                double cloudBase = (temp - dew) / 4.4 * 1000;

                data[i][3] = String.valueOf(chillFactor);

                data[i][4] = String.valueOf(cloudBase);

                model.addRow(data[i]);

            }

            JTable jtable = new JTable(model);
            pnl.setLayout(new BorderLayout());
            JScrollPane tableContainer = new JScrollPane(jtable);

            pnl.add(tableContainer, BorderLayout.CENTER);
            screen.setBackground(Color.ORANGE);
            screen.getContentPane().add(pnl);
            screen.pack();

            screen.setVisible(true);
            screen.setIconImage(Toolkit.getDefaultToolkit().getImage("Users\\mihirptel8138\\Desktop\\weather.png"));

        }

        }

}

The qiestion isn't very clear, but it sounds like you need to update the window's contents after the window has alteady been displayed?
If so you need to separate the code that creates the window from the code that populates the fields with actual data. Then you can re-call the population method whenever the data is changed.