ho modificato il sorgente creando l'oggetto tabella nel main e dichiarando static i vettori rows e cols ed ora non mi da errori in compilazione, il problema è che mi si apre il frame senza niente dentro

codice:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.Color.*;
import java.net.*;
import java.sql.*;
import java.util.*;

public class struttura extends JFrame
{
	private static JPanel tasti;
	private static JTextArea tabella;
	private static Vector cols, rows;
	
	public static void main(String[] args) {
		JFrame f = new JFrame();
		Container cont = f.getContentPane();
		tasti = new JPanel();
		
		connettiAlDb();
		JTable tabella = new JTable(rows, cols);
		
		tasti = new JPanel();
		tasti.setLayout(new BorderLayout());
		tasti.add(tabella, BorderLayout.NORTH);
		
		cont.add(tasti);
		f.pack();
		f.setDefaultCloseOperation(EXIT_ON_CLOSE);
		f.show();
	}
	
	public static void connettiAlDb() {
		try {
			Class.forName("com.mysql.jdbc.Driver").newInstance();
		}
		catch (Exception E) {
			System.err.println("Impossibile caricare il driver");
			E.printStackTrace();
		}
		try {
			System.out.println("Connessione...");
			Connection c = DriverManager.getConnection("jdbc:mysql://localhost/edicola?user=ilc0rv0");
			System.out.println("Connesso: " + c);
			Statement stmt = c.createStatement();
			ResultSet res = stmt.executeQuery("SELECT * FROM quotidiani");
			//----------------------------------------------------------
			Vector cols = new Vector();
 			cols.addElement("testata");
 			cols.addElement("pr netto");
			
 			Vector rows = new Vector();
 			while (res.next()) {
 				Vector vett = new Vector(); 
 				vett.addElement(res.getString("testata")); 
 				vett.addElement(res.getString("pr_netto")); 
 				rows.addElement(vett); 
			}
			
 			//---------------------------------------------------------------
			
		}
		catch (SQLException E) {
			System.out.println ("SQLException:  " + E.getMessage());
			System.out.println ("SQLState:      " + E.getSQLState());
			System.out.println ("VendorError:   " + E.getErrorCode());
		}
	}
}