私の JTable が JFrame に表示されないのはなぜですか?

public class accCreator extends JFrame {
    // Use a BorderLayout for easy component placement
    private JPanel main;
    private JTable tbl_Accounts;
    // ...

    public accCreator() {
        super("Account Manager");
        // Use a BorderLayout
        setLayout(new BorderLayout());

        // Create and add JTable to the center
        tbl_Accounts = new JTable(data, columnNames);
        JScrollPane scrollPane = new JScrollPane(tbl_Accounts);
        add(scrollPane, BorderLayout.CENTER);

        // ...
    }
    // ...
}