TableTest.java

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

class TableTest {

    public TableTest(final String title) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                makeUI(title);
            }
        });
    }

    public void makeUI(String title) {
        new MainFrame(title);
    }

    public static void main(String[] args) {
        new TableTest("ウィンドウ");
    }
}

class MainFrame extends JFrame {

    public MainFrame(String title) {
        super(title);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel table_panel = new TablePanel();
        JTextArea text_area = new JTextArea("テキストエリア");

        getContentPane().add(
                new JSplitPane(JSplitPane.VERTICAL_SPLIT, new JScrollPane(
                        table_panel), new JScrollPane(text_area)));
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }
}

class TablePanel extends JPanel {
    private String[] columnNames = { "x", "y" };
    private Object[][] data = { { "a", 1 }, { "b", 2 }, { "c", 3 }, };

    JTable _table_pane = new JTable(data, columnNames);
    TableAddPanel _add_pane = new TableAddPanel();

    public TablePanel() {
        super(new BorderLayout());
        add(new JScrollPane(_table_pane), BorderLayout.CENTER);
        add(_add_pane, BorderLayout.SOUTH);
    }
}

class TableAddPanel extends JPanel {
    public TableAddPanel() {
        super(new BorderLayout());
        JTextField text_field = new JTextField();
        JButton bu = new JButton("追加");
        add(text_field, BorderLayout.CENTER);
        add(bu, BorderLayout.EAST);
    }
}