Strange (Nullpointer) Excep. during Eventdispatching (JFileChooser).

Question

Hi, sometimes I receive this (complete) stack trace (see below).
It seems do appear at random, even if no JFilechooser is opened. During initialization of my program there are created some instances of JFilechooser, but I can't figure out what the problem is.
Cause I taught the setFileSelected action would only take place if you open a Filechooser. But it has been raised, even if there had never been any Filechooser open.
The first time I received this I thought, it would be an error of the jvm, but then the same error reappeared more than once.
I'm using the 1.4.1_01 jre.
It seems to be a problem with the event queue, but what is going wrong.
Has anyone has ever faced such a problem and can give any clue or idea, how to fix it?
Any help appreciated.
Thanks a lot in advance.
Greetings Michael
java.lang.NullPointerException
     at javax.swing.plaf.metal.MetalFileChooserUI.setFileSelected(Unknown Source)
     at javax.swing.plaf.metal.MetalFileChooserUI$DelayedSelectionUpdater.run(Unknown Source)
     at java.awt.event.InvocationEvent.dispatch(Unknown Source)
     at java.awt.EventQueue.dispatchEvent(Unknown Source)
     at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
     at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
     at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

Hi Leif,
Hi Michael,
It could be one of these bugs that are still open:
http://developer.java.sun.com/developer/bugParade/bugs/4822786.html (no tripple-clicking)
http://developer.java.sun.com/developer/bugParade/bugs/4759922.html (no file deletion)
I've read them, but none of them matches my problem exactly.
If neither of these matches your problem, could you post >a stack trace?The number is changing randomly.
java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 9
    at java.util.Vector.get(Unknown Source)
    at javax.swing.plaf.basic.BasicDirectoryModel.getElementAt(Unknown Source)
    at javax.swing.plaf.basic.BasicListUI.updateLayoutState(Unknown Source)
    at javax.swing.plaf.basic.BasicListUI.maybeUpdateLayoutState(Unknown Source)
    at javax.swing.plaf.basic.BasicListUI.getCellBounds(Unknown Source)
    at javax.swing.JList.getCellBounds(Unknown Source)
    at javax.swing.JList.ensureIndexIsVisible(Unknown Source)
    at javax.swing.plaf.metal.MetalFileChooserUI.ensureIndexIsVisible(Unknown Source)
    at javax.swing.plaf.metal.MetalFileChooserUI.doDirectoryChanged(Unknown Source)
    at javax.swing.plaf.metal.MetalFileChooserUI.access$2600(Unknown Source)
    at javax.swing.plaf.metal.MetalFileChooserUI$12.propertyChange(Unknown Source)
    at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(Unknown Source)
    at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(Unknown Source)
    at javax.swing.JComponent.firePropertyChange(Unknown Source)
    at javax.swing.JFileChooser.setCurrentDirectory(Unknown Source)
    at de.gruenewald.michael.PartyJukebox.PlayList.initFileChoosers(PlayList.java:192)
    at de.gruenewald.michael.PartyJukebox.PlayList.<init>(PlayList.java:96)
    at de.gruenewald.michael.PartyJukebox.PlayList.getReference(PlayList.java:148)
    at de.gruenewald.michael.PartyJukebox.GUI.<init>(GUI.java:91)
    at de.gruenewald.michael.PartyJukebox.GUI.main(GUI.java:217)The Filechooser isn't visible and this exception is risen
during the startup of the Gui (No clicking!). It occurs very seldom at the start of my app.
Perhaps this may be caused, by the fileFilters. There may be less files visible than stored in the dir.
So perhaps some additional code for checking this out could fix this problem.
Do you mean that you are getting the exception even when >using
invokeLater()?No, invokeLater uses a Thread and Exception raised their aren't displayed or logged normally, So I can't tell you , if this really solves the problem or if it is just hidden.
By the way I'm catching the Event-Dispatching-thread, with:
System.setProperty("sun.awt.exception.handler",HandleAllExceptionOfEventDispatching.class.getName());    I try to use a ThreadLoggingGrooup for the scheduled Thread and will tell you about the results here later (cause of the Exception is really seldom raised.)
I will also use try to use it for the first problem (NullPointerExcep.).
SwingUtilities.invokeLater(new Thread(RuntimeObjects.getReference().getLoggingThreadGroup() ,new Runnable(){
            ConfigData config = ConfigData.getReference();
            public void run(){
                if ( config.getDefaultDirForPlayLists() != null){
                    File file = new File(config.getDefaultDirForPlayLists());
                    if( file.exists() && file.canRead() && file.isDirectory() ){
                        PlayList.this.load.setCurrentDirectory(file);
                        PlayList.this.save.setCurrentDirectory(file);
public ThreadGroup getLoggingThreadGroup(){
        loggingThreadGroup = new ThreadGroup("LoggingForThreads"){
            PrintStream errLog = RuntimeObjects.getReference().getErrorLog();
            public void uncaughtException(Thread t, Throwable e){
                if (!(e instanceof ThreadDeath) ){
                    if ( errLog == null){ 
                        errLog.println(e.getMessage());
                        e.printStackTrace(errLog);
                    e.printStackTrace();
        return loggingThreadGroup;
    } Cheers,
/LeifI also post my initFileChoosers:
private void initFileChoosers(){
        load = new JFileChooser();
        save = new JFileChooser();
        AllPlaylistsFilter all = new AllPlaylistsFilter();
        PlayListFilter playFilter = new PlayListFilter();
        PlsFilter plsFilter = new PlsFilter();
        M3uFilter m3u = new M3uFilter();
        //save.removeChoosableFileFilter(save.getFileFilter());
        //load.removeChoosableFileFilter(load.getFileFilter());
        save.setAcceptAllFileFilterUsed(false);
        load.setAcceptAllFileFilterUsed(false);
        load.addChoosableFileFilter(all);
        load.addChoosableFileFilter(playFilter);
        load.addChoosableFileFilter(plsFilter);
        load.addChoosableFileFilter(m3u);
        save.addChoosableFileFilter(all);
        save.addChoosableFileFilter(playFilter);
        save.addChoosableFileFilter(plsFilter);
        save.addChoosableFileFilter(m3u);
        JCheckBox relativePaths = new JCheckBox(rb.getString("CheckBox.RelativePaths"),false);
        save.setAccessory(relativePaths);
        load.setFileFilter(all);
        save.setFileFilter(all);
        //SwingUtilities.invokeLater(new Runnable(){
        //    ConfigData config = ConfigData.getReference();
        //    public void run(){
                if ( config.getDefaultDirForPlayLists() != null){
                    File file = new File(config.getDefaultDirForPlayLists());
                    if( file.exists() && file.canRead() && file.isDirectory() ){
                        PlayList.this.load.setCurrentDirectory(file);
                        PlayList.this.save.setCurrentDirectory(file);
       }Example of a FileFilter:
abstract class DefaultFileFilter extends javax.swing.filechooser.FileFilter{
    public String getExtension(){ return ".ppl"; }
class AllPlaylistsFilter extends DefaultFileFilter{
     public boolean accept(File pathname) {
        if ( pathname.isDirectory() ) return true;
        String name = pathname.getPath();
        int pos = name.lastIndexOf('.');
        String extension = name.substring(pos+1);
        if ( extension.equalsIgnoreCase("m3u") || extension.equalsIgnoreCase("pls") || extension.equalsIgnoreCase("ppl") ) return true;
        return false;
     public String getDescription(){ return "All Playlists"; }
     public String getExtension(){ return ".m3u"; }
}Cheers Michael