Java – JTable does not display column headers

This is my first time using GUI, so I'm not sure what caused the problem My uni mission The project aims to develop a "product management" plan for various purposes Except for GUI, the whole process has been completed. That's why I don't know why this JTable won't display column headers This is the code (by the way, using miglayout)

package sepm.s2012.e0727422.gui;

import sepm.s2012.e0727422.service.*;

import java.awt.*;
import javax.swing.*;

import net.miginfocom.swing.MigLayout;


public class MainFrame {

    /** Start all services **/
//  IProductService ps = new ProductService();
//  IInvoiceService is = new InvoiceService();
//  IOrderService os = new OrderService();

    /** Frame **/
    private JFrame frame;
    private JTabbedPane tab;

    public static void main(String[] args) {
        new MainFrame();
    }


    public MainFrame() {

        frame = new JFrame("Product control and management system");
        frame.setVisible(true);
        frame.setSize(800,600);
        frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);

        /** TABBED PANE options and parameters **/
        tab = new JTabbedPane();
        ImageIcon icon = null; // TODO
        tab.addTab("Products",icon,tabProducts(),"Add/Update/Delete products");
        tab.addTab("Invoices",tabInvoices(),"Overview of invoices");
        tab.addTab("Cart",tabCart(),"Order new products");
        tab.setSelectedIndex(0);

        frame.add(tab,BorderLayout.CENTER);

    }       
    /**
     * Products Panel tab
     * @return panel
     */
    public JPanel tabProducts() {
        JPanel panel = new JPanel(new MigLayout("","20 [] 20","10 [] 10 [] 10 [] 10"));

        JLabel label = new JLabel("List of all available products");
        JButton add = new JButton("Add product");
        JButton update = new JButton("Update product");
        // Below is a test table,will be replace by products in DB
        String[] tableTitle = new String[] {"ID","Name","Type","Price","In stock"};
        String[][] tableData = new String[][] {{"1","Item 1","Type 1","0.00","0"},{"2","Item 2","Type 2",{"3","Item 3","Type 3",{"4","Item 4","Type 4","0"}};
        JTable table = new JTable(tableData,tableTitle);

        panel.add(label,"wrap,span");
        panel.add(table,span");
        panel.add(add);
        panel.add(update);

        return panel;
    }

    public JPanel tabInvoices() {
        JPanel panel = new JPanel(new MigLayout());
        return panel;
    }

    public JPanel tabCart() {
        JPanel panel = new JPanel(new MigLayout());
        return panel;
    }
}

Solution

First, add the table to the JScrollPane:

JScrollPane scrollpane = new JScrollPane(table);

Then add the scroll pane to your layout:

panel.add(scrollpane,span");

Secondly, add all components to the framework and display them as follows at the end of the method:

//...
frame.add(tab,BorderLayout.CENTER);

frame.validate();
frame.setVisible(true);