Java - No dibuja una JTable dentro de un JTabbedPane

package com.JFram;

import java.awt.BorderLayout;

import java.awt.EventQueue;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JScrollPane;

import javax.swing.border.EmptyBorder;

import javax.swing.table.DefaultTableModel;

import javax.swing.JTabbedPane;

import javax.swing.JTable;

public class Ultimo extends JFrame {

	private JPanel contentPane;

	private final JPanel panel_4 = new JPanel();

	private JTable table;

	String[] columnNames = {"Núm.", "Carrera", "Grado", "Institución",

			"Especialidad", "Cédula","Fecha Grad."};

	Object[][] data = {};

	//array de String's con los títulos de las columnas

	DefaultTableModel modelo= new DefaultTableModel(data, columnNames);

	/**

	 * Launch the application.

	 */

	public static void main(String[] args) {

		EventQueue.invokeLater(new Runnable() {

			public void run() {

				try {

					Ultimo frame = new Ultimo();

					frame.setVisible(true);

				} catch (Exception e) {

					e.printStackTrace();

				}

			}

		});

	}

	/**

	 * Create the frame.

	 */

	public Ultimo() {

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		setBounds(0, 0, 800, 650);

		//setBounds(100, 100, 450, 300);

		contentPane = new JPanel();

		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));

		setContentPane(contentPane);

		contentPane.setLayout(null);

		JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);

		tabbedPane.setBounds(12, 46, 758, 504);

		contentPane.add(tabbedPane);

		JPanel panel_1 = new JPanel();

		tabbedPane.addTab("Profesional", null, panel_1, null);

		panel_1.setLayout(null);

		panel_4.setBounds(12, 159, 729, 291);

		panel_1.add(panel_4);

		panel_4.setLayout(null);

		JScrollPane scroll = new JScrollPane();

		scroll.setBounds(9, 271, 709, -260);

		table = new JTable(modelo);

		table.setBounds(44, 209, 652, -162);

		scroll.setViewportView (table);

		panel_4.add(scroll);

	}

}