HyperlinkListener problem!!

Hi All,
I have implemented a hyperlink listener on my JEditorpane.
The problem is that the links are not URL's in the propper sense. They are links to the top and the bottom of the page i.e.
Bottom.
Can anyone please tell me why this is not working? I cannot get evt.getURL() - it's throwing a null pointer exception which makes me think that the href is not in a recognised format.
Hoping someone can please help!!
Thanks,
jackie.

anyhow this is my test case , works fine with me :
import javax.swing.*;
import java.awt.*;
import javax.swing.event.*;
import javax.swing.text.html.*;
public class Test extends JFrame implements HyperlinkListener{
 JEditorPane pane;
 public Test(){
 try{
 pane = new JEditorPane();
 pane.setEditable ( false );
 pane.addHyperlinkListener( this );
 pane.setContentType( "text/html" );
 //pane.setText( "<html><body><h2>Hello...</h2><img src=file:///E:/jprogs/temp/images/logo.gif><body></html>" );
 pane.setPage( getClass().getResource("test.htm") );
 getContentPane().add( new JScrollPane(pane) );
 }catch( Exception e ){
 e.printStackTrace();
 setSize( 400, 400 );
 setLocation( 100, 100 );
 public void hyperlinkUpdate ( HyperlinkEvent e ) {
 if ( e.getEventType () == HyperlinkEvent.EventType.ACTIVATED ) {
 if ( e instanceof HTMLFrameHyperlinkEvent ) {
 HTMLFrameHyperlinkEvent evt = ( HTMLFrameHyperlinkEvent )e;
 HTMLDocument doc = ( HTMLDocument )pane.getDocument ();
 doc.processHTMLFrameHyperlinkEvent ( evt );
 } else {
 try {
 pane.setPage ( e.getURL () );
 } catch ( Throwable t ) {
 JOptionPane.showMessageDialog( null, e.getURL() + " not found ", null, JOptionPane.ERROR_MESSAGE );
 t.printStackTrace();
 public static void main( String[] args ){
 new Test().setVisible( true );
/===========================================
HTML :
<pre>
<html><body>
 <h2>Hello...</h2><img src=images/logo.gif>
 <a name=top></a>
 yahoo.com
 top
 
 
 top
<body></html>
</pre>

Similar Messages

JEditorPane and HyperlinkListener Problems

Here's my code:
public class WizardHelpScreen extends JFrame implements HyperlinkListener {
private Image theIcon = new ImageIcon(getClass().getResource("icon.gif")).getImage();
private JEditorPane helpPane;
private JScrollPane helpScrollPane;
public WizardHelpScreen() {
     super("Help Documents");
     setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setIconImage(theIcon);
        startHelp();
public void startHelp() {
     helpPane = new JEditorPane();
     helpScrollPane = new JScrollPane(helpPane);
     helpPane.setEditable(false);
            helpPane.addHyperlinkListener(this);
            getContentPane().add(helpPane);
           setLocation(230,230);
           setPreferredSize(new Dimension(640,480));
           pack();
        setVisible(true);
            try {
                  helpPane.setPage("file:///c:/japps/HelpTestTwo.html");
         } catch(IOException ex) {
                   JOptionPane.showMessageDialog(null,"Unable to load helpfile.","Error",JOptionPane.ERROR_MESSAGE);
                   helpPane.setText("Error. Unable to load help file. Please reinstall the application or contact support.");
public void hyperlinkUpdate(HyperlinkEvent e) {
        if(e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
             Document doc = helpPane.getDocument();
                try {
                    URL url = e.getURL();
                    helpPane.setPage(url);
                } catch (IOException io) {
                 JOptionPane.showMessageDialog(null, "Can't follow link","Invalid Input",JOptionPane.ERROR_MESSAGE);
                 helpPane.setDocument(doc);
}It opens the html document just fine, and even activates the hyperlink in the first html document. The problem is in the second document that is shown after clicking the link in the first document, the links in the second document don't work anymore. It's like the HyperlinkListener deactivated or something. What am I doing wrong?

Nevermind, there was a typo in my HTML that caused the problem.

HTML Link problem (Urgent!)

I'm writing a prrogram that displays an HTML file. I used a JEditorPane. I tryed using the hyperlinkListener but it doesn't work! here's the class I wrote...
can anyone help please?
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import browser.*;
import java.net.*;
import javax.swing.event.*;
* Classe :
* Description :
* Societe : Medias France
* @version 1.0
public class Aide extends JFrame implements HyperlinkListener
     BrowserInterface bI;
     URL url1;
     static Interface parent;
     public Aide(String titre, Interface i)
          super(titre);
          parent = i;
          getContentPane().setLayout(new BorderLayout());
          //bI = new BrowserInterface(jp);
          setBounds(10,10,800,600);
          addWindowListener(new WindowAdapter()
               public void windowClosing(WindowEvent e)
               quit(null);
          try
               url1 = new URL("file:/home/darkazan/java/BDO/tablegen-1.8/help/help.html");
               //bI.URL_Process(url1);
          catch (MalformedURLException e)
               System.out.println("probleme " + e.toString());
          JEditorPane editorPane = new JEditorPane();
     editorPane.setEditable(false);
     try
     editorPane.setPage(url1);
     catch (IOException e)
     System.err.println("Attempted to read a bad URL: " + url1);
     JScrollPane editorScrollPane = new JScrollPane(editorPane);
          editorScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
     editorScrollPane.setPreferredSize(new Dimension(800, 600));
     getContentPane().add(editorScrollPane, "Center");
     pack();
     setVisible(true);
     public void hyperlinkListener(HyperlinkEvent e)
          if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED)
     // do something on HL click
System.out.println("ouverture");
          if (e.getEventType() == HyperlinkEvent.EventType.ENTERED)
          // do something on mouse over HL
     // do something on HL click
     System.out.println("bbbbbbbbbbbbbbbbbbbb");
if (e.getEventType() == HyperlinkEvent.EventType.EXITED)
// do something on HL click
System.out.println("ggggggggggggggggggg");
// do something on mouse moved away from HL
     public void hyperlinkUpdate(HyperlinkEvent e)
     public static void main(String[] args)
          Aide aide1 = new Aide("Help", parent);
     * Quitter l'application
     * @param     e L'evenement recu
     * @return     Sans objet.
     void quit(ActionEvent e)
          parent.bAide.setEnabled(true);
          dispose();
}

also check your file protocol it should look like this: file:/// with three slashes(i think?)
here Mr. Urgent, my html viewer: (and it works) ;P
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.accessibility.*;
import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import java.net.MalformedURLException;
import java.io.IOException;
public class iROCHelp extends JPanel implements HyperlinkListener{
//ATTRIBUTES
JEditorPane html;
private static boolean HelpShowing = false;
private static JFrame selTopic;
//METHODS
//Constructor
public iROCHelp(java.net.URL URLstr){
//setBorder(new EmptyBorder());
setLayout(new BorderLayout());
try{
URL url = URLstr;
if(url != null){
html = new JEditorPane(url);
html.setEditable(false);
html.addHyperlinkListener(this);
JScrollPane scroller = new JScrollPane();
JViewport vp = scroller.getViewport();
vp.add(html);
vp.setBackingStoreEnabled(true);
add(scroller, BorderLayout.CENTER);
catch (MalformedURLException e){
System.out.println("Malformed URL: " + e);
catch (IOException e){
System.out.println("IOException: " + e);
}//HelpTopic CONSTRUCTOR
public void hyperlinkUpdate(HyperlinkEvent e){
if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED){
linkActivated(e.getURL());
}//hyperlinkUpdate
protected void linkActivated(URL u){
Cursor c = html.getCursor();
Cursor waitCursor = Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR);
html.setCursor(waitCursor);
SwingUtilities.invokeLater(new PageLoader(u, c));
}//linkActivated
class PageLoader implements Runnable{
PageLoader(URL u, Cursor c){
url = u;
cursor = c;
public void run(){
if (url == null){
// restore the original cursor
html.setCursor(cursor);
Container parent = html.getParent();
parent.repaint();
else{
Document doc = html.getDocument();
try{
html.setPage(url);
catch (IOException ioe){
html.setDocument(doc);
finally{
// schedule the cursor to revert after
// the paint has happended.
url = null;
SwingUtilities.invokeLater(this);
}//else
}//run
URL url;
Cursor cursor;
}//PageLoader
public static void spawnHelp(java.net.URL URLStr){
if (!HelpShowing){
selTopic = new JFrame();
selTopic.getContentPane().setLayout(new BorderLayout());
selTopic.getContentPane().add(new iROCHelp(URLStr),BorderLayout.CENTER);
Dimension dim = selTopic.getToolkit().getScreenSize();
selTopic.setLocation((int)dim.getWidth()/2-selTopic.getWidth()/2,(int)dim.getHeight()/2-selTopic.getHeight()/2);
selTopic.setSize(500, 400);
selTopic.setTitle("Remote Operators Console Help");
selTopic.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
closeHelp();
}//windowClosing
selTopic.show();
HelpShowing = true;
}//if help showing
}//spawnHelp
public static void closeHelp(){
if (HelpShowing){
selTopic.dispose();
HelpShowing = false;
}//closeHelp
}//HelpTopic CLASS

Problem with Hyperlink in JEditorPane!!

hi all!
I have some problem.
I create html page with hyperlink to myProgram.jar and when i open this html page in JEditorPane and click on hyperlink i have the some text but my program don't run.
How write HyperlinkListener for run the my program and setUrl for open other html pages.
thanks!

In the future, Swing related questions should be posted in the Swing forum.
But, there is no need to repost the question because you can just read the JEditorPane API to find an example of how to write a HyperlinkListener.

No compilation error but have problems when running.

Hello all,
After implementing the examples given from the TextComponentJavaDemo in Java Tutorials I tried to get the fonts to change text in the JEditorPane but to no avail.
The problem I am having now is some java.lang.Null.PointerException .
The errors are shown as follows:
Exception in thread "main" java.lang.NullPointerException
at guiClient.createActionTable<guiClient.java :191>
at guiClient.<init> <guiClient.java:52>
at guiClient.main <guiClient.java:308>
Here is the whole code for the syntax but it cannot be compiled:
/* * My GUI Client */
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
//for HTML Headers
import javax.swing.text.StyledEditorKit.*;
import javax.swing.text.html.HTMLEditorKit.*;
import javax.swing.text.html.*;
import javax.swing.event.HyperlinkListener;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkEvent.EventType;
import javax.swing.text.html.HTMLFrameHyperlinkEvent;
import javax.swing.text.*;
//for layout managers
import java.awt.event.*;
//for action and window events
import java.io.*;
import java.net.*;
import java.awt.GraphicsEnvironment;
import java.util.HashMap;
public class guiClient extends JFrame implements ActionListener {
protected static final String textFieldString = "JTextField";
protected static final String loadgraphicString = "LoadGraphic";
protected static final String connectString = "Connect";
static JEditorPane editorPane;
static JPanel layoutPanel = new JPanel(new BorderLayout());
static JPanel controlPanel = new JPanel(new BorderLayout());
static PrintStream out;
static DrawPanel dPanel;
static DrawControls dControls;
static AnimationButtons aControls;
static String userString;
static JTextField userName = new JTextField();
public static JMenuBar menuBar;
private static JButton connectbutton = new JButton("Connect");
static boolean CONNECTFLAG = false;
AbstractDocument doc;
HashMap actions;
//create the gui interface
public guiClient() {
 super("My Client");
//Create a regular text field.
 JTextField textField = new JTextField(10);
 textField.setActionCommand(textFieldString);
 textField.addActionListener(this);
//Create an editor pane.
 createActionTable(editorPane); //From TextComponentDemo
 editorPane = new JEditorPane();
 editorPane.setContentType("text");
 editorPane.setEditable(true);
//set up HTML editor kit
 HTMLDocument m_doc = new HTMLDocument();
 editorPane.setDocument(m_doc);
 HTMLEditorKit hkit = new HTMLEditorKit();
 editorPane.setEditorKit( hkit );
 editorPane.addHyperlinkListener(new HyperListener());
//Create whiteboard
 dPanel = new DrawPanel();
 dControls = new DrawControls(dPanel);
 aControls = new AnimationButtons (dPanel);
 JPanel whiteboard = new JPanel();
 whiteboard.setLayout(new BorderLayout());
 whiteboard.setPreferredSize(new Dimension(300,300));
 whiteboard.add("Center",dPanel);
 whiteboard.add("South",dControls);
 // whiteboard.add("North",aControls);
 JScrollPane editorScrollPane = new JScrollPane(editorPane);
 editorScrollPane.setVerticalScrollBarPolicy( JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
 editorScrollPane.setPreferredSize(new Dimension(250, 145));
 editorScrollPane.setMinimumSize(new Dimension(50, 50));
// StyledDocument styledDoc = editorPane.getStyledDocument();
//put everything in a panel
 JPanel contentPane = new JPanel();
 contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));
//add whiteboard
 contentPane.add(whiteboard);
//add editor box
 contentPane.add(editorScrollPane);
//add spacer
 contentPane.add(Box.createRigidArea(new Dimension(0,5)));
//add textfield
 contentPane.add(textField);
//set up layout pane
 layoutPanel.add(BorderLayout.WEST,new Label("Name: ")); //add a label
 layoutPanel.add(BorderLayout.CENTER, userName ); //add textfield for user names
 layoutPanel.add(BorderLayout.SOUTH, connectbutton);//add dropdown box for fonts
 contentPane.add(layoutPanel);
 contentPane.add(controlPanel);
 contentPane.add(aControls);
//Create the menu bar.
 menuBar = new JMenuBar();
 setJMenuBar(menuBar);
//Build the first menu.
 JMenu menu = new JMenu("File");
 JMenu styleMenu = createStyleMenu();
 menu.setMnemonic(KeyEvent.VK_F);
 menuBar.add(menu);
 menuBar.add(styleMenu);
//a group of JMenuItems
 JMenuItem menuItem = new JMenuItem("Load Graphic", KeyEvent.VK_L);
 menu.add(menuItem);
 menuItem.setActionCommand(loadgraphicString);
 menuItem.addActionListener(this);
 connectbutton.setActionCommand(connectString);
 connectbutton.addActionListener(this);
 setContentPane(contentPane);
protected JMenu createStyleMenu() {
 JMenu menu = new JMenu("Style");
 Action action = new StyledEditorKit.BoldAction();
 action.putValue(Action.NAME, "Bold");
 menu.add(action);
 action = new StyledEditorKit.ItalicAction();
 action.putValue(Action.NAME, "Italic");
 menu.add(action);
 action = new StyledEditorKit.UnderlineAction();
 action.putValue(Action.NAME, "Underline");
 menu.add(action);
 menu.addSeparator();
 menu.add(new StyledEditorKit.FontSizeAction("12", 12));
 menu.add(new StyledEditorKit.FontSizeAction("14", 14));
 menu.add(new StyledEditorKit.FontSizeAction("18", 18));
 menu.addSeparator();
 menu.add(new StyledEditorKit.FontFamilyAction("Serif",
 "Serif"));
 menu.add(new StyledEditorKit.FontFamilyAction("SansSerif",
 "SansSerif"));
 menu.addSeparator();
 menu.add(new StyledEditorKit.ForegroundAction("Red",
 Color.red));
 menu.add(new StyledEditorKit.ForegroundAction("Green",
 Color.green));
 menu.add(new StyledEditorKit.ForegroundAction("Blue",
 Color.blue));
 menu.add(new StyledEditorKit.ForegroundAction("Black",
 Color.black));
 return menu;
 protected SimpleAttributeSet[] initAttributes(int length) {
 //Hard-code some attributes.
 SimpleAttributeSet[] attrs = new SimpleAttributeSet[length];
 attrs[0] = new SimpleAttributeSet();
 StyleConstants.setFontFamily(attrs[0], "SansSerif");
 StyleConstants.setFontSize(attrs[0], 16);
 attrs[1] = new SimpleAttributeSet(attrs[0]);
 StyleConstants.setBold(attrs[1], true);
 attrs[2] = new SimpleAttributeSet(attrs[0]);
 StyleConstants.setItalic(attrs[2], true);
 attrs[3] = new SimpleAttributeSet(attrs[0]);
 StyleConstants.setFontSize(attrs[3], 20);
 attrs[4] = new SimpleAttributeSet(attrs[0]);
 StyleConstants.setFontSize(attrs[4], 12);
 attrs[5] = new SimpleAttributeSet(attrs[0]);
 StyleConstants.setForeground(attrs[5], Color.red);
 return attrs;
 private void createActionTable(JTextComponent textComponent) {
 actions = new HashMap();
 Action[] actionsArray = textComponent.getActions();
 for (int i = 0; i < actionsArray.length; i++) {
 Action a = actionsArray;
actions.put(a.getValue(Action.NAME), a);
private Action getActionByName(String name) {
return (Action)(actions.get(name));
static private void insertTheHTML(JEditorPane editor, String html, int location) throws IOException {
 HTMLEditorKit kit = (HTMLEditorKit) editor.getEditorKit();
 Document doc = editor.getDocument();
 StringReader reader = new StringReader(html);
 try {
 kit.read(reader, doc, location);
 } catch (BadLocationException e) {}
//listen for actions being performed and process them
public void actionPerformed(ActionEvent e) {
//if the action is from the textfield (e.g. user hits enter)
 if (e.getActionCommand().equals(textFieldString)) {
 JTextField fromUser = (JTextField)e.getSource();
 if (fromUser != null){
//place user text in editor pane
//send message to server
 if (userName.getText() != null) {
 userString = userName.getText().trim();
 out.println(userString + ": " + fromUser.getText());
 fromUser.setText("");
 } else if(e.getActionCommand().equals(connectString)) {
 CONNECTFLAG = true;
} else if (e.getActionCommand().equals(loadgraphicString) ) {
 final JFileChooser fc = new JFileChooser();
 int returnVal = fc.showOpenDialog(this);
 if (returnVal == JFileChooser.APPROVE_OPTION) {
 File file = fc.getSelectedFile();
 dPanel.loadImage(file.getAbsolutePath());
 sendImage(file);
//append text to the editor pane and put it at the bottom
public static void appendText(String text) {
 if (text.startsWith("ID ") ) {
 userString = text.substring(3);
 } else if (text.startsWith("DRAW ") ) {
 if (text.regionMatches(5,"LINE",0,4)) {
dPanel.processLine(text);
 }else if (text.regionMatches(5,"POINTS",0,5)) {
 dPanel.processPoint(text);
 } else if (text.startsWith("IMAGE ") ) {
int len = (new Integer( text.substring(6, text.indexOf(",")))).intValue();
//get x and y coordinates
 byte[] data = new byte[ (int)len ];
 int read = 0;
try {
 while (read < len) {
 data = text.getBytes( text.substring(0, len) );
} catch (Exception e) {}
 Image theImage = null;
 theImage = dPanel.getToolkit().createImage(data);
 dPanel.getToolkit().prepareImage(theImage, -1, -1, dPanel);
 while ((dPanel.getToolkit().checkImage(theImage, -1, -1, dPanel) & dPanel.ALLBITS) == 0) {}
 dPanel.drawPicture(0, 0, theImage);
} else {
//set current position in editorPane to the end
 editorPane.setCaretPosition(editorPane.getDocument().getLength());
//put text into the editorPane
 try {
 insertTheHTML(editorPane, text, editorPane.getDocument().getLength());
 } catch (IOException e) {}
} //end of appendText(String)
public void sendImage(File file) {
//find length of file
 long len = file.length();
//read file into byte array
 byte[] byteArray = new byte[(int)len];
 try {
 FileInputStream fstream = new FileInputStream(file);
 if (fstream.read(byteArray) < len) {
//error could not load file
 } else {
 out.println("IMAGE " + len + ",");
 out.write(byteArray, 0, (int)len); //write file to stream
 } catch(Exception e){}
//run the client
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
//Create and set up the window.
final guiClient frame = new guiClient();
//Display the window.
frame.pack();
frame.setVisible(true);
public static void main(String[] args) {
 String ipAddr=null, portNr=null;
 if (args.length != 2) {
 System.out.println("USAGE: java guiClient IP_Address port_number");
 System.exit(0);
 } else {
 ipAddr = args[0];
 portNr = args[1];
 JFrame frame = new guiClient();
 frame.addWindowListener(new WindowAdapter() {
 public void windowClosing(WindowEvent e) { System.exit(0); }
 frame.pack();
 frame.setVisible(true);
 while(CONNECTFLAG == false){}
//sames as previous client,
//set up connection and then listen for messages from the Server
 String socketIP = ipAddr;
 int port = Integer.parseInt(portNr);
//the IP address of the machine where the server is running
 Socket theSocket = null;
//communication line to the server
 out = null;
//for message sending
 BufferedReader in = null;
//for message receiving
 try {
 theSocket = new Socket(socketIP, port );
//try to connect
 out = new PrintStream(theSocket.getOutputStream());
 dPanel.out = out;
//for client to send messages
 in = new BufferedReader(new InputStreamReader(theSocket.getInputStream()));
 BufferedReader userIn = new BufferedReader(new InputStreamReader(System.in));
 String fromServer;
 while ((fromServer = in.readLine()) != null) {
 appendText(fromServer);
 if (fromServer.equals("BYE")) {
 appendText("Connection Closed");
 break;
 out.close();
//close all streams
 in.close();
 theSocket.close();
//close the socket
 } catch (UnknownHostException e) {
//if the socket cannot be openned
 System.err.println("Cannot find " + socketIP);
 System.exit(1);
 } catch (IOException e) { //if the socket cannot be read or written
 System.err.println("Could not make I/O connection with " + socketIP);
 System.exit(1);
 javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
Can someone tell me what's the problem with the syntax?

For your nullPointerException, you have to create your textPane before calling createActionTable editorPane = new JEditorPane();
 createActionTable(editorPane); //From TextComponentDemoAlso, I would like to point out the following :
- you're creating your guiClient twice in the main method : at the beginning and at the end through the createAndShowGUI.
- for no apparent reason, all your member fields are declared static.
- naming conventions : class names must start with a capital letter.

HyperLinkListener and relative jumps within a document

hi,
sorry for not knowing the terminology but I've added a HyperLinkListener to a JEditorPane containing some html, and its working fine for URLs that are actually urls. The problem is that the same html also contains text like
Environment Settings on Linux and Solaris
and later on a
<a name="Startup"/>
Does anyone have any idea how to make the page jump like you'd expect? There seem to be two problems
a) how to detect one of these relative-within-page links
b) how to find where they point to (and maybe even how to scroll there)
any help really appreciated,
asjf

Further questions:
You might explain what "does not show on the landscape pages" means. Do you mean you see nothing of the rotation, or it shows, but always appears non-rotated?
Are you looking at it in Entry (AFEMain or Entry plug-in); or are you looking at printed pages - which goes to the question of what kind of output you are producing; and is it perhaps a PDF or some other non-printer specific output that is viewed through some other application, like Acrobat, Internet Explorer, etc.?
And please indicate whether this is a static (predefined) bar code you have designed or whether it is a field that you have mapped data into. And are you allowing the page to determine the rotation - based upon the portrait and landscape settings - or are you choosing the rotation property in the design of the object trying to anticipate having it appear correctly?
But to reiterate, the version and patch level will probably be key in the event this was a known bug that has already been corrected.

Questionable Legality: HyperlinkListener without URLs

Hey guys,
My goal is to have website-style links in a JEditorPane that cause certain behaviors in my GUI when the user clicks them.
The SSCCE below works exactly how I'd want it to. The only problem is, I feel a bit dirty using a HyperlinkListener in such a seemingly non-standard way. Is there a better/standard way to accomplish my goal? I thought of using a JTextPane with clickable JLabels inserted where my hyperlinks now go, but using the HyperlinkListener seems simpler.
Here is the potentially shameful SSCCE I came up with:
import java.awt.Color;
import javax.swing.*;
import javax.swing.event.*;
public class EditorLinkTest {
 public EditorLinkTest() {
 JFrame frame = new JFrame("EditorPane Link Test");
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 final JEditorPane textComponent = new JEditorPane();
 textComponent.setEditable(false);
 textComponent.setContentType("text/html");
 String text = "Background color: " +
 "<a href='red'>Click here</a> for red. "+
 "<a href='white'>Click here</a> for white. ";
 textComponent.setText(text);
 textComponent.addHyperlinkListener(new HyperlinkListener() {
 public void hyperlinkUpdate(HyperlinkEvent e) {
 if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
 try {
 //e.getURL() would cause a NPE, for obvious reasons
 String link = e.getDescription();
 System.out.println("Link: " + link);
 if(link.contains("red")){
 textComponent.setBackground(Color.RED);
 else if(link.contains("white")){
 textComponent.setBackground(Color.WHITE);
 catch (Exception ex) {
 System.err.println("Error: " + ex);
 JScrollPane scrollPane = new JScrollPane(textComponent, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
 frame.add(scrollPane);
 frame.setSize(200, 200);
 frame.setVisible(true);
 public static void main(String[] args) {
 new EditorLinkTest();
}So, what say you? Am I just being paranoid about what is a "valid" use of a HyperlinkListener? Or should I man up and change my GUI so that it uses a JTextPane with clickable components that cause the desired behavior? Do I not fix what ain't broke, or do I delete this dirty code before anybody else sees it?
I'm on the fence myself, so any input would be appreciated.

I see nothing on my stdout (I'm using JDK1.6.0_11, WinXP) when I click the links... And I'm not able to debug why (never used HyperlinkEvents before).That's really weird. I'm using JDK1.6.0_17, WinXP. I'll have to investigate whether it works other platforms, I suppose :(Works home (JDK 1.6.0_11, WInXP too). Beats me...
Anyway at least I could investigate forward...
Instead of "parsing" the event's description, couldn't you get its Element property, and look at the Element's attributes?I've been playing with this for a while now, but I can't seem to find anything useful from HyperlinkEvent.getSourceElement().anything. Am I missing something?I tried this. Seems to work:
 public void hyperlinkUpdate(HyperlinkEvent e) {
 if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
 try {
 //e.getURL() would cause a NPE, for obvious reasons
 // String link = e.getDescription();
 AttributeSet attrs = e.getSourceElement().getAttributes();
 AttributeSet aTagAttrs = (AttributeSet)attrs.getAttribute(HTML.Tag.A);
 String link = (String)aTagAttrs.getAttribute(HTML.Attribute.HREF);
 System.out.println("href VALUE: " + link);
 if(link.equals("red")){
 textComponent.setBackground(Color.RED);
 else if(link.equals("white")){
 textComponent.setBackground(Color.WHITE);
 catch (Exception ex) {
 System.err.println("Error: " + ex);
 }I don't know what worse... Parsing the undocumented description string, vs relying on the poorly-documented types and hierarchy of AttributeSets... Assuming this latter is reliable, I much prefer it: after all once digged through it, makes sense that there is an <A> tag, whose HREF attribute contains the link string. What makes less sense is that I had to inspect the private attributes of JDK classes in a debugger to discover the types and values of those! >o(

Hyperlinklistener in jeditorpane

I am trying to insert a hyperlinklistener on a jeditorpane and I am having some errors. I need some help. I can't find the right package to get rid of these errors.
Here are the errors
D:\Quincy\Java\mybrowser\MyBrowser.java:22: cannot resolve symbol
symbol : method addHyperLinkListener (MyBrowser.Hyperactive)
location: class javax.swing.JEditorPane
          editorPane.addHyperLinkListener(new Hyperactive());
^
D:\Quincy\Java\mybrowser\MyBrowser.java:82: cannot resolve symbol
symbol : class HTMLFrameHyperlinkEvent
location: class MyBrowser.Hyperactive
          if (e instanceof HTMLFrameHyperlinkEvent) {
^
D:\Quincy\Java\mybrowser\MyBrowser.java:83: cannot resolve symbol
symbol : class HTMLFrameHyperlinkEvent
location: class MyBrowser.Hyperactive
          HTMLFrameHyperlinkEvent evt = (HTMLFrameHyperlinkEvent)e;
^
D:\Quincy\Java\mybrowser\MyBrowser.java:83: cannot resolve symbol
symbol : class HTMLFrameHyperlinkEvent
location: class MyBrowser.Hyperactive
          HTMLFrameHyperlinkEvent evt = (HTMLFrameHyperlinkEvent)e;
^
D:\Quincy\Java\mybrowser\MyBrowser.java:84: cannot resolve symbol
symbol : class HTMLDocument
location: class MyBrowser.Hyperactive
          HTMLDocument doc = (HTMLDocument)pane.getDocument();
^
D:\Quincy\Java\mybrowser\MyBrowser.java:84: cannot resolve symbol
symbol : class HTMLDocument
location: class MyBrowser.Hyperactive
          HTMLDocument doc = (HTMLDocument)pane.getDocument();
^
6 errors
Tool completed with exit code 1
Here is the code
This is a browser demo
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import java.net.*;
import java.io.*;
import java.awt.*;
public class MyBrowser extends JPanel
     public MyBrowser()
          //Create editor pane
          JEditorPane editorPane = createEditorPane();
          editorPane.addHyperLinkListener(new Hyperactive());
          //Put the editor pane in a scroll pane.
          JScrollPane editorScrollPane = new JScrollPane(editorPane);
          editorScrollPane.setVerticalScrollBarPolicy(
                          JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
          editorScrollPane.setPreferredSize(new Dimension(800, 600));
          editorScrollPane.setMinimumSize(new Dimension(300, 300));
          add(editorScrollPane);
     private JEditorPane createEditorPane()
          JEditorPane editorPane = new JEditorPane();
          editorPane.setEditable(false);
          URL helpURL = MyBrowser.class.getResource("GettingStarted.htm");
          if (helpURL != null) {
              try
                  editorPane.setPage(helpURL);
              catch (IOException e)
                  System.err.println("Attempted to read a bad URL: " + helpURL);
          else
              System.err.println("Couldn't find file: " + helpURL);
          return editorPane;
     private static void createGUI()
          JFrame theFrame = new JFrame();
          theFrame.setTitle("Quincy's browser");
          theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          JComponent newComponent = new MyBrowser();
          newComponent.setOpaque(true);
          theFrame.setContentPane(newComponent);
          theFrame.pack();
          theFrame.setVisible(true);
     public static void main(String[]args)
          createGUI();
     class Hyperactive implements HyperlinkListener
         public void hyperlinkUpdate(HyperlinkEvent e) {
               if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
                JEditorPane pane = (JEditorPane) e.getSource();
                if (e instanceof HTMLFrameHyperlinkEvent) {
                    HTMLFrameHyperlinkEvent evt = (HTMLFrameHyperlinkEvent)e;
                    HTMLDocument doc = (HTMLDocument)pane.getDocument();
                    doc.processHTMLFrameHyperlinkEvent(evt);
                } else {
                    try {
                     pane.setPage(e.getURL());
                    } catch (Throwable t) {
                     t.printStackTrace();

you've got two quite simple problems from what i can see. you can get rid of a lot of those errors by import that html package
import javax.swing.text.html.*;
and secondly, change:
editorPane.addHyperLinkListener(new Hyperactive());
to
editorPane.addHyperlinkListener(new Hyperactive());
in other words, just lower case the 'L' in link
I've tried the code with the changes and it seems to compile ok,
Good luck.

A problem with threads

I am trying to implement some kind of a server listening for requests. The listener part of the app, is a daemon thread that listens for connections and instantiates a handling daemon thread once it gets some. However, my problem is that i must be able to kill the listening thread at the user's will (say via a sto button). I have done this via the Sun's proposed way, by testing a boolean flag in the loop, which is set to false when i wish to kill the thread. The problem with this thing is the following...
Once the thread starts excecuting, it will test the flag, find it true and enter the loop. At some point it will LOCK on the server socket waiting for connection. Unless some client actually connects, it will keep on listening indefinatelly whithought ever bothering to check for the flag again (no matter how many times you set the damn thing to false).
My question is this: Is there any real, non-theoretical, applied way to stop thread in java safely?
Thank you in advance,
Lefty

This was one solution from the socket programming forum, have you tried this??
public Thread MyThread extends Thread{
     boolean active = true;
     public void run(){
          ss.setSoTimeout(90);
          while (active){
               try{
                    serverSocket = ss.accept();
               catch (SocketTimeoutException ste){
               // do nothing
     // interrupt thread
     public void deactivate(){
          active = false;
          // you gotta sleep for a time longer than the
          // accept() timeout to make sure that timeout is finished.
          try{
               sleep(91);
          }catch (InterruptedException ie){
          interrupt();
}

A problem with Threads and MMapi

I am tring to execute a class based on Game canvas.
The problem begin when I try to Play both a MIDI tone and to run an infinit Thread loop.
The MIDI tone "Stammers".
How to over come the problem?
Thanks in advance
Kobi
See Code example below:
import java.io.IOException;
import java.io.InputStream;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.media.Manager;
import javax.microedition.media.MediaException;
import javax.microedition.media.Player;
public class MainScreenCanvas extends GameCanvas implements Runnable {
 private MainMIDlet parent;
 private boolean mTrucking = false;
 Image imgBackgound = null;
 int imgBackgoundX = 0, imgBackgoundY = 0;
 Player player;
 public MainScreenCanvas(MainMIDlet parent)
 super(true);
 this.parent = parent;
 try
 imgBackgound = Image.createImage("/images/area03_bkg0.png");
 imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
 imgBackgoundY = this.getHeight() - imgBackgound.getHeight();
 catch(Exception e)
 System.out.println(e.getMessage());
 * starts thread
 public void start()
 mTrucking = true;
 Thread t = new Thread(this);
 t.start();
 * stops thread
 public void stop()
 mTrucking = false;
 public void play()
 try
 InputStream is = getClass().getResourceAsStream("/sounds/scale.mid");
 player = Manager.createPlayer(is, "audio/midi");
 player.setLoopCount(-1);
 player.prefetch();
 player.start();
 catch(Exception e)
 System.out.println(e.getMessage());
 public void run()
 Graphics g = getGraphics();
 play();
 while (true)
 tick();
 input();
 render(g);
 * responsible for object movements
 private void tick()
 * response to key input
 private void input()
 int keyStates = getKeyStates();
 if ((keyStates & LEFT_PRESSED) != 0)
 imgBackgoundX++;
 if (imgBackgoundX > 0)
 imgBackgoundX = 0;
 if ((keyStates & RIGHT_PRESSED) != 0)
 imgBackgoundX--;
 if (imgBackgoundX < this.getWidth() - imgBackgound.getWidth())
 imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
 * Responsible for the drawing
 * @param g
 private void render(Graphics g)
 g.drawImage(imgBackgound, imgBackgoundX, imgBackgoundY, Graphics.TOP | Graphics.LEFT);
 this.flushGraphics();
}

You can also try to provide a greater Priority to your player thread so that it gains the CPU time when ever it needs it and don't harm the playback.
However a loop in a Thread and that to an infinite loop is one kind of very bad programming, 'cuz the loop eats up most of your CPU time which in turn adds up more delays of the execution of other tasks (just as in your case it is the playback). By witting codes bit efficiently and planning out the architectural execution flow of the app before start writing the code helps solve these kind of issues.
You can go through [this simple tutorial|http://oreilly.com/catalog/expjava/excerpt/index.html] about Basics of Java and Threads to know more about threads.
Regds,
SD
N.B. And yes there are more articles and tutorials available but much of them targets the Java SE / EE, but if you want to read them here is [another great one straight from SUN|http://java.sun.com/docs/books/tutorial/essential/concurrency/index.html] .
Edited by: find_suvro@SDN on 7 Nov, 2008 12:00 PM

J2ME problem with threads

Hi all,
I would like to ask you for a help. I need to write a small program at my university. I started to write a midlet which function would be to countdown time for sports activities. I woul like to start a new thread - the one that counts down - and at the same time make the main thread sleep. After the "countdown" thread finishes, the main thread wakes up and waits for user input. The problem is that when the "countdown" thread finishes his work, I've got Uncaught exception java/lang/NullPointerException. error and the midlet halts.
Below you can find the code
import java.lang.*;
import java.util.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class intervals extends MIDlet implements CommandListener
public Display ekran;
private SweepCanvas sweeper;
private Form rundy;
private TextField round0, round1, round2, round3, round4, round5, round6, round7, round8;
private long czas,x;
private Command exitCommand;
private Command addRound;
private Command delRound;
private Command start;
private TextField repeat;
private Form odliczanie;
private Alert ostrz;
Licznik thread;
String test;
StringItem test1;
int parz,i,j,k;
static int l;
int ilrund;
int ilpowt;
Item sec;
long sec1;
public intervals()
 rundy = new Form("Interwały sportowe");
 exitCommand = new Command("Wyjście", Command.EXIT, 2);
 addRound = new Command("Dodaj","Dodaj rundę", Command.ITEM,1);
 delRound = new Command("Usuń","Usuń ostatnią rundę", Command.ITEM,1);
 start = new Command("Start", Command.ITEM,1);
 odliczanie = new Form("Odliczanie");
 TextField dodaj(TextField kolej)
 kolej=new TextField("Podaj czas (s) rundy "+parz,null, 4, TextField.NUMERIC);//stworzenie nowej instancji do wybierania czasu trwania rundy
 if(rundy.size()==0)
 rundy.insert(rundy.size(),kolej);
 else
 rundy.insert(rundy.size()-1, kolej);
 return kolej;
 void odliczanie(TextField round)
 monitor m=new monitor();
 k=Integer.parseInt(round.getString());
 ekran.setCurrent(odliczanie);
 thread=new Licznik(k,odliczanie);
 thread.start();
 ekran.setCurrent(rundy);
public void startApp()// throws MIDletStateChangeException
 rundy.deleteAll();
 repeat = new TextField("Podaj ilość powtórzeń",null,1,TextField.NUMERIC);
 rundy.addCommand(addRound);
 rundy.addCommand(exitCommand);
 rundy.setCommandListener(this);
 Canvas obrazek = new MyCanvas();
 ekran = Display.getDisplay(this);
 ekran.setCurrent(obrazek);
 czas=System.currentTimeMillis();
 while (System.currentTimeMillis()<czas+1000)
 continue;
 ekran.setCurrent(rundy);
public void pauseApp()
public void destroyApp(boolean unconditional)
 notifyDestroyed();
public void commandAction(Command c, Displayable s)
 if (c == exitCommand)
 destroyApp(false);
 notifyDestroyed();
 else if(c==addRound)
 if(rundy.size()==0)//Sprawdzenie ilości elementów w celu poprawnego wyświetlania liczby rund w formie
 parz=1;
 else
 parz=rundy.size();
 switch(parz)
 case 1:
 round0=dodaj(round0);break;
 case 2:
 round1=dodaj(round1);break;
 case 3:
 round2= dodaj(round2);break;
 case 4:
 round3=dodaj(round3);break;
 case 5:
 round4=dodaj(round4);break;
 default:
 ostrz=new Alert("Uwaga","Maksymalna liczba rund wynosi 9", null, AlertType.INFO);
 ostrz.setTimeout(3000);
 ekran.setCurrent(ostrz);
 if(rundy.size()==1)
 rundy.append(repeat);
 rundy.addCommand(start);
 rundy.addCommand(delRound);
 else if(c==delRound)
 if(rundy.size()!=0)
 rundy.delete(rundy.size()-2);
 if (rundy.size()==1)
 rundy.deleteAll();
 if(rundy.size()==0)
 rundy.removeCommand(delRound);
 rundy.removeCommand(start);
 else if(c==start)
 ilrund=rundy.size()-1;
 if(this.repeat.size()>0)
 ilpowt=Integer.parseInt(this.repeat.getString());
 ekran = Display.getDisplay(this);
 for (i=1; i<=ilpowt;i++)
 odliczanie= new Form("Odliczanie");
 for (j=0;j<ilrund;j++)
 switch(j)
 case 0:
 odliczanie(round0);
 break;
 case 1:
 odliczanie(round1);
 break;
 case 2:
 odliczanie(round2);
 break;
 case 3:
 odliczanie(round3);
 break;
 case 4:
 odliczanie(round4);
 break;
 case 5:
 odliczanie(round5);
 break;
 case 6:
 odliczanie(round6);
 break;
 case 7:
 odliczanie(round7);
 break;
 case 8:
 odliczanie(round8);
 break;
class Licznik extends Thread
 int czas1,k;
 Form forma;
 monitor m;
 public Licznik(int k,Form formap)
 czas1=k;
 forma=formap;
 public synchronized void run()
 while(czas1>0)
 forma.deleteAll();
 forma.append("Czas pozostały (s): "+czas1);
 try{Thread.sleep(1000);} catch(InterruptedException e){e.printStackTrace();}
 czas1--;
 if(czas1<=0)
 m.put();
 }and monitor class
public class monitor
boolean busy=false;
synchronized void get()
 if(!busy)
 try
 wait();
 }catch(InterruptedException e){e.printStackTrace();}
 notify();
synchronized void put()
 if(busy)
 try
 wait();
 }catch(InterruptedException e){e.printStackTrace();}
 busy=true;
 notify();
}Can anybody help me with this?

Groovemaker,
Your Licznik class has a member m of type monitor, which has not been instantiated (in other words is null) hence, when calling m.put() you get NullPointerException. Please also mind, that using Thread.sleep(1000) is not an accurate way of measuring time.
If I may, please use recommended for Java class naming conventions - some of your names use lower case, while other don't which is confusing to the reader.
Daniel

Problem with threads within applet

Hello,
I got an applet, inside this applet I have a singleton, inside this singleton I have a thread.
this thread is running in endless loop.
he is doing something and go to sleep on and on.
the problem is,
when I refresh my IE6 browser I see more than 1 thread.
for debug matter, I did the following things:
inside the thread, sysout every time he goes to sleep.
sysout in the singleton constructor.
sysout in the singleton destructor.
the output goes like this:
when refresh the page, the singleton constructor loading but not every refresh, sometimes I see the constructor output and sometimes I dont.
The thread inside the singleton is giving me the same output, sometime I see more than one thread at a time and sometimes I dont.
The destructor never works (no output there).
I don't understand what is going on.
someone can please shed some light?
thanks.
btw. I am working with JRE 1.1
this is very old and big applet and I can't convert it to something new.

Ooops. sorry!
I did.
     public void start() {
     public void stop() {
     public void destroy() {
          try {
               resetAll();
               Configuration.closeConnection();
               QuoteItem.closeConnection();
          } finally {
               try {
                    super.finalize();
               } catch (Throwable e) {
                    e.printStackTrace();
     }

Problem with Threads and a static variable

I have a problem with the code below. I am yet to make sure that I understand the problem. Correct me if I am wrong please.
Code functionality:
A timer calls SetState every second. It sets the state and sets boolean variable "changed" to true. Then notifies a main process thread to check if the state changed to send a message.
The problem as far I understand is:
Assume the timer Thread calls SetState twice before the main process Thread runs. As a result, "changed" is set to true twice. However, since the main process is blocked twice during the two calls to SetState, when it runs it would have the two SetState timer threads blocked on its synchronized body. It will pass the first one, send the message and set "changed" to false since it was true. Now, it will pass the second thread, but here is the problem, "changed" is already set to false. As a result, it won't send the message even though it is supposed to.
Would you please let me know if my understanding is correct? If so, what would you propose to resolve the problem? Should I call wait some other or should I notify in a different way?
Thanks,
B.D.
Code:
private static volatile boolean bChanged = false;
private static Thread objMainProcess;
   protected static void Init(){
        objMainProcess = new Thread() {
            public void run() {
                while( objMainProcess == Thread.currentThread() ) {
                   GetState();
        objMainProcess.setDaemon( true );
        objMainProcess.start();
    public static void initStatusTimer(){
        if(objTimer == null)
             objTimer = new javax.swing.Timer( 1000, new java.awt.event.ActionListener(){
                public void actionPerformed( java.awt.event.ActionEvent evt){
                          SetState();
    private static void SetState(){
        if( objMainProcess == null ) return;
        synchronized( objMainProcess ) {
            bChanged = true;
            try{
                objMainProcess.notify();
            }catch( IllegalMonitorStateException e ) {}
    private static boolean GetState() {
        if( objMainProcess == null ) return false;
        synchronized( objMainProcess ) {
            if( bChanged) {
                SendMessage();
                bChanged = false;
                return true;
            try {
                objMainProcess.wait();
            }catch( InterruptedException e ) {}
            return false;
    }

Thanks DrClap for your reply. Everything you said is right. It is not easy to make them alternate since SetState() could be called from different places where the state could be anything else but a status message. Like a GREETING message for example. It is a handshaking message but not a status message.
Again as you said, There is a reason I can't call sendMessage() inside setState().
The only way I was able to do it is by having a counter of the number of notifies that have been called. Every time notify() is called a counter is incremented. Now instead of just checking if "changed" flag is true, I also check if notify counter is greater than zero. If both true, I send the message. If "changed" flag is false, I check again if the notify counter is greater than zero, I send the message. This way it works, but it is kind of a patch than a good design fix. I am yet to find a good solution.
Thanks,
B.D.

Problem with threads running javaw

Hi,
Having a problem with multi thread programming using client server sockets. The program works find when starting the the application in a console using java muti.java , but when using javaw multi.java the program doesnt die and have to kill it in the task manager. The program doesnt display any of my gui error messages either when the server disconnect the client. all works find in a console. any advice on this as I havent been able to understand why this is happening? any comment would be appreciated.
troy.

troy,
Try and post a minimum code sample of your app which
does not work.
When using javaw, make sure you redirect the standard
error and standard output streams to file.
Graeme.Hi Graeme,
I dont understand what you mean by redirection to file? some of my code below.
The code works fine under a console, code is supposed to exit when the client (the other server )disconnects. the problem is that but the clientworker side of the code still works. which under console it doesnt.
public class Server{
ServerSocket aServerSocket;
Socket dianosticsSocket;
Socket nPortExpress;
ClientListener aClientListener;
LinkedList queue = new LinkedList();
int port = 0;
int clientPort = 0;
String clientName = null;
boolean serverAlive = true;
* Server constructor generates a server
* Socket and then starts a client threads.
* @param aPort      socket port of local machine.
public Server(int aPort, String aClientName, int aClientPort){
port = aPort;
clientName = aClientName;
clientPort = aClientPort;
try{
// create a new thread
aServerSocket = new ServerSocket(port) ;
// connect to the nPortExpress
aClientListener = new ClientListener(InetAddress.getByName(clientName), clientPort, queue,this);
// aClientListener.setDaemon(true);
aClientListener.start();
// start a dianostic port
DiagnosticsServer aDiagnosticsServer = new DiagnosticsServer(port,queue,aClientListener);
// System.out.println("Server is running on port " + port + "...");
// System.out.println("Connect to nPort");
catch(Exception e)
// System.out.println("ERROR: Server port " + port + " not available");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Server port " + port + " not available", JOptionPane.ERROR_MESSAGE);
serverAlive = false;
System.exit(1);
while(serverAlive&&aClientListener.hostSocket.isConnected()){
try{
// connect the client
Socket aClient = aServerSocket.accept();
//System.out.println("open client connection");
//System.out.println("client local: "+ aClient.getLocalAddress().toString());
// System.out.println("client localport: "+ aClient.getLocalPort());
// System.out.println("client : "+ aClient.getInetAddress().toString());
// System.out.println("client port: "+ aClient.getLocalPort());
// make a new client thread
ClientWorker clientThread = new ClientWorker(aClient, queue, aClientListener, false);
// start thread
clientThread.start();
catch(Exception e)
//System.out.println("ERROR: Client connection failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client connection failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end constructor Server
void serverExit(){
     JOptionPane.showMessageDialog(null, "Server ","ERROR: nPort Failure", JOptionPane.ERROR_MESSAGE);
     System.exit(1);
}// end class Server
*** connect to another server
public class ClientListener extends Thread{
InetAddress hostName;
int hostPort;
Socket hostSocket;
BufferedReader in;
PrintWriter out;
boolean loggedIn;
LinkedList queue;      // reference to Server queue
Server serverRef; // reference to main server
* ClientListener connects to the host server.
* @param aHostName is the name of the host eg server name or IP address.
* @param aHostPort is a port number of the host.
* @param aLoginName is the users login name.
public ClientListener(InetAddress aHostName, int aHostPort,LinkedList aQueue,Server aServer)      // reference to Server queue)
hostName = aHostName;
hostPort = aHostPort;
queue = aQueue;
serverRef = aServer;
// connect to the server
try{
hostSocket = new Socket(hostName, hostPort);
catch(IOException e){
//System.out.println("ERROR: Connection Host Failed");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort Failed", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} // end constructor ClientListener
** multi client connection server
ClientWorker(Socket aSocket,LinkedList aQueue, ClientListener aClientListener, boolean diagnostics){
queue = aQueue;
addToQueue(this);
client = aSocket;
clientRef = aClientListener;
aDiagnostic = diagnostics;
} // end constructor ClientWorker
* run method is the main loop of the server program
* in change of handle new client connection as well
* as handle all messages and errors.
public void run(){
boolean alive = true;
String aSubString = "";
in = null;
out = null;
loginName = "";
loggedIn = false;
while (alive && client.isConnected()&& clientRef.hostSocket.isConnected()){
try{
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
if(aDiagnostic){
out.println("WELCOME to diagnostics");
broadCastDia("Connect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
out.println("WELCOME to Troy's Server");
broadCastDia("Connect : client "+client.getInetAddress().toString());
     out.flush();
String line;
while(((line = in.readLine())!= null)){
StringTokenizer aStringToken = new StringTokenizer(line, " ");
if(!aDiagnostic){
broadCastDia(line);
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
else{
if(line.equals("GETIPS"))
getIPs();
else{
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
} // end while
catch(Exception e){
// System.out.println("ERROR:Client Connection reset");
                         JOptionPane.showMessageDialog(null, (e.toString()),"ERROR:Client Connection reset", JOptionPane.ERROR_MESSAGE);
try{
if(aDiagnostic){
broadCastDia("Disconnect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
broadCastDia("Disconnect : client "+client.getInetAddress().toString());
     out.flush();
// close the buffers and connection;
in.close();
out.close();
client.close();
// System.out.println("out");
// remove from list
removeThreadQueue(this);
alive = false;
catch(Exception e){
// System.out.println("ERROR: Client Connection reset failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client Connection reset failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end method run
* method run - Generates io stream for communicating with the server and
* starts the client gui. Run also parses the input commands from the server.
public void run(){
boolean alive = true;
try{
// begin to life the gui
// aGuiClient = new ClientGui(hostName.getHostName(), hostPort, loginName, this);
// aGuiClient.show();
in = new BufferedReader(new InputStreamReader(hostSocket.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(hostSocket.getOutputStream()));
while (alive && hostSocket.isConnected()){
String line;
while(((line = in.readLine())!= null)){
System.out.println(line);
broadCast(line);
} // end while
} // end while
catch(Exception e){
//     System.out.println("ERRORa Connection to host reset");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort reset", JOptionPane.ERROR_MESSAGE);
try{
hostSocket.close();
     }catch(Exception a){
     JOptionPane.showMessageDialog(null, (a.toString()),"ERROR: Exception", JOptionPane.ERROR_MESSAGE);
alive = false;
System.exit(1);
} // end method run

Problem with Threads and "plase wait..."-Window

Hi everyone,
I have a problem that I'm not able to solve in any way... I have a time-consuming task (a file decryption) which I execute in a separate thread; I've used the SwingWorker class, like suggested by sun-tutorial, and it works right. The problem is that I have to wait that the decryption have finished before continuing with program-execution. Therefore I would like to display a "please wait"-window while the task runs. I've tryed all the possible ways I know but the problem is always the same: the waitWindow is displayed empty, the bounds are painted but the contents no; it's only painted when the decrypt-task has finished. Please help me, I have no more resources....
decrypt-file code:
public class DecryptFile {
private String cryptedFileNameAndPath;
private ByteArrayInputStream resultStream = null;
// need for progress
private int lengthOfTask;
private int current = -1;
private String statMessage;
public DecryptFile(String encZipFileNameAndPath) {
    cryptedFileNameAndPath = encZipFileNameAndPath;
    //Compute length of task...
    // 0 for indeterminate
    lengthOfTask = 0;
public ByteArrayInputStream getDecryptedInputStream() {
    return this.resultStream;
   * Called from ProgressBarDemo to start the task.
public void go() {
    current = -1;
    final SwingWorker worker = new SwingWorker() {
      public Object construct() {
        return new ActualTask();
    worker.start();
   * Called from ProgressBarDemo to find out how much work needs
   * to be done.
public int getLengthOfTask() {
    return lengthOfTask;
   * Called from ProgressBarDemo to find out how much has been done.
public int getCurrent() {
    return current;
public void stop() {
    current = lengthOfTask;
   * Called from ProgressBarDemo to find out if the task has completed.
public boolean done() {
    if (current >= lengthOfTask)
      return true;
    else
      return false;
public String getMessage() {
    return statMessage;
   * The actual long running task. This runs in a SwingWorker thread.
class ActualTask {
    ActualTask () {
      current = -1;
      statMessage = "";
      resultStream = AIUtil.getInputStreamFromEncZip(cryptedFileNameAndPath); //here the decryption happens
      current = 0;
      statMessage = "";
}The code that calls decryption and displays waitWindow
      final WaitSplash wS = new WaitSplash("Please wait...");
      final DecryptFile cryptedTemplate = new DecryptFile (this.templateFile);
      cryptedTemplate.go();
      while (! cryptedTemplate.done()) {
        try {
          wait();
        } catch (Exception e) { }
      this.templateInputStream = cryptedTemplate.getDecryptedInputStream();
      wS.close();Thanks, thanks, thanks in advance!
Edoardo

Maybe you can try setting the priority of the long-running thread to be lower? so that the UI will be more responsive...

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