How to update a java frame with changed content I want to update a frame or just the panel with updated content. What do I use for this Here is where i want to revalidate the frame or repaint mainpanel or whatever will work I have tried a number of things, but none of them have worked. public void actionPerformed(ActionEvent e) { //System.out.println(e.getActionCommand()); if (e.getActionCommand().equals("advance")) { multi--; // Revalidate update repaint here <<<<<<<<<<<<<<<<<<< } else if (e.getActionCommand().equals("reverse")) { multi++; // Revalidate update repaint here <<<<<<<<<<<<<<<<<<< } else { openURL(e.getActionCommand()); } } Here is the whole java file /* * * */ package build; import java.lang.reflect.Method; import javax.swing.JOptionPane; import java.util.Arrays; import java.util.*; import java.util.ArrayList; import javax.swing.*; import javax.swing.AbstractButton; import javax.swing.JScrollPane; import javax.swing.JButton; import javax.swing.JPanel; import javax.swing.JFrame; import javax.swing.ImageIcon; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; /* * ButtonDemo.java requires the following files: * images/right.gif * images/middle.gif * images/left.gif */ public class StockTable extends JPanel implements ActionListener { static int multi = 1; int roll = 0; static TextVars textvars = new TextVars(); static final String[] browsers = { "firefox", "opera", "konqueror", "epiphany", "seamonkey", "galeon", "kazehakase", "mozilla", "netscape" }; JFrame frame; JPanel mainpanel, panel1, panel2, panel3, panel4, panel2left, panel2center, panel2right; JButton stknames_btn[] = new JButton[textvars.getNumberOfStocks()]; JLabel label[] = new JLabel[textvars.getNumberOfStocks()]; JLabel headlabel, dayspan, namelabel; JRadioButton radioButton; JButton button; JScrollPane scrollpane; int wid = 825; public JPanel createContentPane() { mainpanel = new JPanel(); mainpanel.setPreferredSize(new Dimension(wid, 800)); mainpanel.setLayout(new GridBagLayout()); GridBagConstraints c = new GridBagConstraints(); panel1 = new JPanel(); panel1.setPreferredSize(new Dimension(wid, 25)); c.gridx = 0; c.gridy = 0; c.insets = new Insets(0,0,0,0); mainpanel.add(panel1, c); // Panel 2------------ panel2 = new JPanel(); panel2.setPreferredSize(new Dimension(wid, 51)); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0,0,0,0); mainpanel.add(panel2, c); panel2left = new JPanel(); panel2left.setPreferredSize(new Dimension(270, 51)); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2left, c); panel2center = new JPanel(); panel2center.setPreferredSize(new Dimension(258, 51)); c.gridx = 1; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2center, c); panel2right = new JPanel(); panel2right.setPreferredSize(new Dimension(270, 51)); c.gridx = 2; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2right, c); // ------------------ panel3 = new JPanel(); panel3.setLayout(new GridBagLayout()); scrollpane = new JScrollPane(panel3); scrollpane.setPreferredSize(new Dimension(wid, 675)); c.gridx = 0; c.gridy = 2; c.insets = new Insets(0,0,0,0); mainpanel.add(scrollpane, c); ImageIcon leftButtonIcon = createImageIcon("images/right.gif"); //b1 = new JButton("Disable middle button", leftButtonIcon); //b1.setVerticalTextPosition(AbstractButton.CENTER); //b1.setHorizontalTextPosition(AbstractButton.LEADING); //aka LEFT, for left-to-right locales //b1.setMnemonic(KeyEvent.VK_D); //b1.setActionCommand("disable"); //Listen for actions on buttons 1 //b1.addActionListener(this); //b1.setToolTipText("Click this button to disable the middle button."); //Add Components to this container, using the default FlowLayout. //add(b1); headlabel = new JLabel("hellorow1"); c.gridx = 0; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(headlabel, c); radioButton = new JRadioButton("Percentage"); c.gridx = 2; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(radioButton, c); radioButton = new JRadioButton("Days Range"); c.gridx = 3; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(radioButton, c); radioButton = new JRadioButton("Open / Close"); c.gridx = 4; c.gridy = 0; c.insets = new Insets(0, 0, 0,0 ); panel1.add(radioButton, c); button = new JButton("<<"); button.setPreferredSize(new Dimension(50, 50)); button.setActionCommand("reverse"); button.addActionListener(this); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2left.add(button, c); dayspan = new JLabel("hellorow2"); dayspan.setHorizontalAlignment(JLabel.CENTER); dayspan.setVerticalAlignment(JLabel.CENTER); dayspan.setPreferredSize(new Dimension(270, 50)); c.gridx = 1; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2center.add(dayspan, c); button = new JButton(">>"); button.setPreferredSize(new Dimension(50, 50)); button.setActionCommand("advance"); button.addActionListener(this); if (multi == 0) { button.setEnabled(false); } else { button.setEnabled(true); } c.gridx = 2; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2right.add(button, c); int availSpace_int = textvars.getStocks().size()-textvars.getNumberOfStocks()*7; ArrayList<String[]> stocknames = textvars.getStockNames(); ArrayList<String[]> stocks = textvars.getStocks(); for (int column = 0; column < 8; column++) { for (int row = 0; row < textvars.getNumberOfStocks(); row++) { if (column==0) { if (row==0) { namelabel = new JLabel(stocknames.get(0)[0]); namelabel.setVerticalAlignment(JLabel.CENTER); namelabel.setHorizontalAlignment(JLabel.CENTER); namelabel.setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0, 0, 0, 0); panel3.add(namelabel, c); } else { stknames_btn[row] = new JButton(stocknames.get(row)[0], leftButtonIcon); stknames_btn[row].setVerticalTextPosition(AbstractButton.CENTER); stknames_btn[row].setActionCommand(stocknames.get(row)[1]); stknames_btn[row].addActionListener(this); stknames_btn[row].setToolTipText("go to Google Finance "+stocknames.get(row)[0]); stknames_btn[row].setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0, 0, 0, 0); //scrollpane.add(stknames[row], c); panel3.add(stknames_btn[row], c); } } else { label[row]= new JLabel(textvars.getStocks().get(columnMulti(multi))[1]); label[row].setBorder(BorderFactory.createLineBorder(Color.black)); label[row].setVerticalAlignment(JLabel.CENTER); label[row].setHorizontalAlignment(JLabel.CENTER); label[row].setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0,0,0,0); panel3.add(label[row], c); } } } return mainpanel; } public void actionPerformed(ActionEvent e) { //System.out.println(e.getActionCommand()); if (e.getActionCommand().equals("advance")) { multi--; } else if (e.getActionCommand().equals("reverse")) { multi++; } else { openURL(e.getActionCommand()); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = StockTable.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } public static void openURL(String url) { String osName = System.getProperty("os.name"); try { if (osName.startsWith("Mac OS")) { Class<?> fileMgr = Class.forName("com.apple.eio.FileManager"); Method openURL = fileMgr.getDeclaredMethod("openURL", new Class[] {String.class}); openURL.invoke(null, new Object[] {url}); } else if (osName.startsWith("Windows")) { Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + url); } else { //assume Unix or Linux boolean found = false; for (String browser : browsers) if (!found) { found = Runtime.getRuntime().exec( new String[] {"which", browser}).waitFor() == 0; if (found) Runtime.getRuntime().exec(new String[] {browser, url}); } if (!found) throw new Exception(Arrays.toString(browsers)); } } catch (Exception e) { JOptionPane.showMessageDialog(null, "Error attempting to launch web browser\n" + e.toString()); } } int reit = 0; int start = textvars.getStocks().size()-((textvars.getNumberOfStocks()*5)*7)-1; public int columnMulti(int multi) { reit++; start++; if (reit == textvars.getNumberOfStocks()) { reit = 0; start=start+64; } //start = start - (multi*(textvars.getNumberOfStocks())); return start; } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. JFrame frame = new JFrame("Stock Table"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. StockTable newContentPane = new StockTable(); //newContentPane.setOpaque(true); //content panes must be opaque //frame.setContentPane(newContentPane); frame.setContentPane(newContentPane.createContentPane()); frame.setSize(800, 800); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } }