Can't get the table display my results

Question

OK After some good hours of debugging i am able to display my results on JTable for my queries. But i got another problem now. When i select Query2 from my JComboBox and click on execute button nothing happens, same thing for query3 and 4. The only thing which works is QUERY1 why? what am i doing wrong?
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
import java.awt.event.ActionEvent;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Vector;
public class DatabaseProgramming extends JFrame implements ActionListener{
     static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
     static final String DATABASE_URL = "jdbc:mysql://localhost/employees";
     static final String USERNAME = "jhtp6";
     static final String PASSWORD = "jhtp6";
     private static final String QUERY1 = "SELECT * FROM employees WHERE DEPARTMENTNAME = 'SALES'";
     private static final String QUERY2 = "SELECT * FROM hourlyEmployees WHERE hours >= '30'";
     private static final String QUERY3 = "SELECT * FROM commissionEmployees ORDER BY commissionRate DESC";
     private String names[] = {"QUERY1", "QUERY2", "QUERY3", "QUERY4"};
     private Connection connection;
     private ResultSet resultSet;
     private Statement statement;
     private ResultSetMetaData metaData;
     private JTable resultTable;
     private JComboBox queryBox;
     private JButton button;
     private int number;
     private boolean connectedDatabase = false;
     private DefaultTableModel dtm;
     public static void main(String[] args) {
          DatabaseProgramming frame = new DatabaseProgramming();
          frame.setVisible(true);
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     public DatabaseProgramming() {
          super("Testing Database");
          setLayout(new FlowLayout());
          //dtm = new DefaultTableModel(getColumnName(number),0);
          //     statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
               //         ResultSet.CONCUR_READ_ONLY);
          queryBox = new JComboBox(names);
          queryBox.setEditable(false);
               //queryBox.addActionListener(this);
               button = new JButton("EXECUTE");
               resultTable = new JTable();
               button.addActionListener(this);
               add(queryBox);
               add(button);
               add(resultTable);
               //add(result);
               setSize(400,400);
      public void actionPerformed(ActionEvent e)  {
          String selection = (String)queryBox.getSelectedItem();
                    if(selection.equals(names[0]))
                    validateQuery(QUERY1);
                    if(selection.equals(QUERY2))
                         validateQuery(QUERY2);
                    if(selection.equals(QUERY3))
                         validateQuery(QUERY3);
      public void validateQuery(String query) {
               try {
                    Class.forName(JDBC_DRIVER);
                    connection = DriverManager.getConnection(DATABASE_URL, USERNAME, PASSWORD);
                    System.out.println("Yay Database Connected");
                Vector col = new Vector();
                Vector data = new Vector();
           statement = connection.createStatement();
              resultSet = statement.executeQuery(query);
              metaData = resultSet.getMetaData();
              number = metaData.getColumnCount();
              for(int i=1; i<=number; i++)
                   col.addElement(metaData.getColumnName(i));
              while(resultSet.next()) {
                   Vector row = new Vector();
                   for(int i=1; i<=number; i++)
                        row.addElement(resultSet.getObject(i));
                   data.addElement(row);
             resultTable.setModel(new DefaultTableModel(data,col));
             resultTable.revalidate();
           catch ( SQLException sqlException )
              sqlException.printStackTrace();
              System.exit( 1 );
           catch(ClassNotFoundException e) {
                e.printStackTrace();
           finally
              try                                                       
                 statement.close();                                     
                 connection.close();                                    
              catch ( SQLException sqlException )
                 JOptionPane.showMessageDialog( null,
                    sqlException.getMessage(), "Database error",
                    JOptionPane.ERROR_MESSAGE );
                 System.exit( 1 );
}

Answer 1

One last question how can i display the columnName on my JTable? Add the table to a scroll pane and the scroll pane to the frame.