如何从组合框更新表格的单元格？

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import net.java.dev.designgridlayout.DesignGridLayout;
import java.io.*;
import net.java.dev.designgridlayout.Tag;
import javax.swing.JButton;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;  
import java.sql.*;

class table1
{
JFrame JF;
Container C;
JPanel JP;
JLabel creditLabel;
JComboBox credit;
String[] Credit = {"Vasan Phalke", "Pansare", "Anil Kg", "Suresh"};
String[] Names = {"Name", "Qty", "Rate/ Kg", "Rate/Dzn.", "Total Amt."};
JTable table;
DefaultTableModel model;
JScrollPane scrollPane;

public table1()
{
JF = new JFrame();
JP = new JPanel();
C= JF.getContentPane();
JF.pack();
JF.setLocationRelativeTo(null); 
JF.setVisible(true);    

DesignGridLayout layout = new DesignGridLayout(C);

creditLabel = new JLabel("Credit");
credit = new JComboBox<String>(Credit);
model = new DefaultTableModel(Names,5);
    table =new JTable(model){@Override
public boolean isCellEditable(int arg0, int arg1)
{
    return true;
}
               };


  scrollPane= new JScrollPane(table);

layout.row().grid(creditLabel).add(credit);
layout.emptyRow();
layout.row().grid().add(table);

C.add(JP);
}

public static void main(String args[])
{
new table1();
}
}
import javax.swing.*;
import javax.swing.eve