jtable using sql

import java.sql.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;


public class DisplayQueryResults extends JFrame {

  // java.sql types needed for database processing
  private Connection connection;
  private Statement statement;
  private ResultSet resultSet;
  private ResultSetMetaData rsMetaData;

  //javax.swing types needed for GUI
  private JTable table;
  private JTextArea inputQuery;
  private JButton submitQuery;

  public DisplayQueryResults() {
    //call super class constructor
    super( "Enter Query. Click Submit to See Results." );
    //The url specifying the GMS database to which this program connects using
    //JDBC to connect to a Microsoft ODBC database
    String url = "jdbc: odbc:XXXX";
    String username = "user";
    String password = "password";

    //Load the driver to allow connection to the database
    try {
      Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
      connection = DriverManager.getConnection(
          url, username, password );
    }
    catch ( ClassNotFoundException cnfex ) {
      System.err.println(
          "Failed to load JDBC/ODBC driver." );
      cnfex.printStackTrace();
      System.exit( 1 ); //terminate the program
    }
    catch ( SQLException sqlex ) {
      System.err.println( "Unable to Connect" );
      sqlex.printStackTrace();
      System.exit( 1 );
    }
    // If connected to database, set up GUI
    inputQuery = new JTextArea( "SELECT XXXXX from YYYYY where ZZZZZZZZZZZZZ", 4, 30 );
    submitQuery = new JButton( "Submit query" );
    submitQuery.addActionListener(
        new ActionListener() {
           public void actionPerformed( ActionEvent e )
           {
             if ( e.getSource() == submitQuery )
               getTable();
           }
        }
    );

    JPanel topPanel = new JPanel();
    topPanel.setLayout( new BorderLayout() );
    topPanel.add( new JScrollPane( inputQuery ), BorderLayout.CENTER );
    topPanel.add( submitQuery, BorderLayout.SOUTH );

    table = new JTable( 4, 4 );

    Container c = getContentPane();
    c.setLayout( new BorderLayout() );
    c.add( topPanel, BorderLayout.NORTH );
    c.add( table, BorderLayout.CENTER );

    //getTable();

    setSize( 500, 500 );
    show();
  }

  private void getTable() {

    try {
      String query = inputQuery.getText();

      statement = connection.createStatement();
      resultSet = statement.executeQuery( query );
      displayResultSet( resultSet );
    }
    catch ( SQLException sqlex ) {
      sqlex.printStackTrace();
    }
  }

  private void displayResultSet( ResultSet rs ) throws SQLException {

    //position to first record
    boolean moreRecords = rs.next();
    // If there are no more records, display a message
    if ( ! moreRecords ) {
      JOptionPane.showMessageDialog( this, "ResultSet contained no records" );
      setTitle( "No records to display" );
      return;
    }

    Vector columnHeads = new Vector();
    Vector rows = new Vector();

    try {
      // get column heads
      ResultSetMetaData rsmd = rs.getMetaData();
      for ( int i = 1; i <= rsmd.getColumnCount(); ++i )
        columnHeads.addElement( rsmd.getColumnName( i ));
      //get row data
      do {
        rows.addElement( getNextRow( rs, rsmd ) );
      } while ( rs.next() );

      //display table with ResultSet contents
      table = new JTable( rows, columnHeads );
      JScrollPane scroller = new JScrollPane( table );
      Container c = getContentPane();
      c.remove( 1 );
      c.add( scroller, BorderLayout.CENTER );
      c.validate();
    }catch ( SQLException sqlex ) {
      sqlex.printStackTrace();
    }

  }// end displayResultSet

  private Vector getNextRow( ResultSet rs, ResultSetMetaData rsmd )
      throws SQLException {

    Vector  currentRow = new Vector();

    for ( int i = 1; i <= rsmd.getColumnCount(); ++i )
      switch( rsmd.getColumnType( i ) ) {
          case Types.VARCHAR:
          case Types.LONGVARCHAR:
            currentRow.addElement( rs.getString( i ) );
            break;
          case Types.INTEGER:
            currentRow.addElement(
                new Long( rs.getLong( i ) ) );
            break;
          case Types.DOUBLE:
            currentRow.addElement(
                new Double( rs.getDouble( i ) ) );
          default:
            //System.out.println( "Type was: " + rsmd.getColumnTypeName( i ) );
      }

    return currentRow;
  }

  public void shutDown(){

    try {
      connection.close();
    }catch ( SQLException sqlex ) {
      System.err.println( "Unable to disconnect" );
      sqlex.printStackTrace();
    }
  }

  public static void main( String args[] ) {

    final DisplayQueryResults app = new DisplayQueryResults();

    app.addWindowListener(
        new WindowAdapter() {
           public void windowClosing( WindowEvent e ) {
             app.shutDown();
             System.exit( 0 );
           }
        }
    );
  }
}

JButton addButton = new JButton("add");
addButton.addActionListener(
        new ActionListener() {
           public void actionPerformed( ActionEvent e )
           {
             if ( e.getSource() == addButton )
               refreshTable();
           }
        }
    );