Resize jtable in jscrollpane

Question

Hi,
I have a frame containing a JTable and a panel with buttons. When the window gets resized, I would like that the jtable takes the extra space and that the button panel stays the same. How can I do that? The jtable panel is already the "Center" and both panels stay the same...
Thanks,
Marie
Here's the code:
package test;
import javax.swing.*;
import java.awt.AWTEvent;
import java.awt.event.WindowEvent;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;
public class Testframe extends JFrame {
    private JPanel mainPanel = new JPanel();
    private JPanel buttonPanel = new JPanel();
    private JPanel tablePanel = new JPanel();
    //Button panel
    private JButton applyTableBt = new JButton("Generate Table");
    private JButton addBt = new JButton("Add");
    private JButton editBt = new JButton("Edit");
    private JButton deleteBt = new JButton("Delete");
    private JButton matchBt = new JButton("Find");
    private JButton saveBt = new JButton("Save to file");
    private JButton loadBt = new JButton("Load from file");
     * Constructor.
     * @param a_parent Frame
    protected Testframe() {
        enableEvents(AWTEvent.WINDOW_EVENT_MASK);
        try {
            jbInit();
            this.setResizable(true);
            this.setVisible(true);
            pack();
        } catch (Exception e) {
            e.printStackTrace();
     * Initialization of the dialog.
     * @throws Exception
    private void jbInit() throws Exception {
        this.setTitle("Pattern management - CAT");
        Object[][] data = { {"11", "12", "13", "14", "15", "16", "17", "18"},
                          {"21", "22", "23", "24", "25", "26", "27", "28"}
        Object[] names = {"col1", "col2", "col3", "col4", "col5", "col6",
                         "col7", "col8"};
        JTable table = new JTable(data, names);
        table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
        //table.setColu
        TableColumnModel colModel = table.getColumnModel();
        for (int i = 0; i < table.getColumnCount(); i++) {
            TableColumn column = colModel.getColumn(i);
            column.setPreferredWidth(511);
        JScrollPane scrollPane = new JScrollPane(table);
        tablePanel.add(scrollPane);
        //Layout = vertical box with vertical gap
        buttonPanel.setLayout(new GridLayout(7, 1, 0, 5));
        buttonPanel.add(applyTableBt);
        buttonPanel.add(addBt);
        buttonPanel.add(editBt);
        buttonPanel.add(deleteBt);
        buttonPanel.add(matchBt);
        buttonPanel.add(saveBt);
        buttonPanel.add(loadBt);
        //mainPanel.setLayout(new BorderLayout());
        mainPanel.add(tablePanel, BorderLayout.CENTER);
        mainPanel.add(buttonPanel, BorderLayout.EAST);
        this.setContentPane(mainPanel);
     * Overrides this class to call the good method when the dialog is closed.
     * @param a_windowE WindowEvent
    protected void processWindowEvent(WindowEvent a_windowE) {
        //If it is a request to close the window (X)
        if (a_windowE.getID() == WindowEvent.WINDOW_CLOSING) {
            cancel();
        super.processWindowEvent(a_windowE);
     * Closes the dialog.
    private void cancel() {
        dispose();
    private static void createAndDisplayFrame() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        new Testframe();
    public static void main(String[] args) {
        createAndDisplayFrame();
}

Answer 1

try changing these lines
mainPanel.add(tablePanel, BorderLayout.CENTER);
mainPanel.add(buttonPanel, BorderLayout.EAST);
this.setContentPane(mainPanel);
to this
mainPanel.add(buttonPanel, BorderLayout.EAST);
getContentPane().add(scrollPane, BorderLayout.CENTER);
getContentPane().add(mainPanel, BorderLayout.EAST);