Thread problem.. help

Question

I have a thread execution of my program which reading a text file and in the same time giving the priority to the GUI.
My problem is, if I comment the:
      m_Support.firePropertyChange("", null, null);in the method "setWorkingInstances", my GUI will display the content of the file, otherwise if it's uncomment, my GUI is processing something, and never displays the output but busy. Can anybody help me to solve this problem? I'm headache of this..
m_Support is the object that tells another class that the owner of the m_Support propertychange has been invoked (i hope i'm rite).
public void setBaseInstancesFromFile(final File f) {
    if (m_IOThread == null) {
      m_IOThread = new Thread() {
        public void run() {
          try {
            Reader r = new BufferedReader(new FileReader(f));
            // call the function
            setBaseInstances(new Instances(r));
            r.close();
          catch (Exception ex) {
            //..bla..
          m_IOThread = null;
      m_IOThread.setPriority(Thread.MIN_PRIORITY); // GUI has most priority
      m_IOThread.start();
    } else {
      //..bla..bla..
public void setBaseInstances(Instances inst) {
    m_BaseInstances = inst;
    try {
      Runnable r = new Runnable() {
        public void run() {
          ... bla.. bla..
          // call again another function
          setWorkingInstances(m_BaseInstances);
      if (SwingUtilities.isEventDispatchThread()) {
        r.run();
      } else {
        SwingUtilities.invokeAndWait(r);
    } catch (Exception ex) {
       ..bla.. bla..     
public void setWorkingInstances(Instances inst) {
    if (m_WorkingInstances != inst) {
      m_WorkingInstances = inst;
      ... bla.. bla.. bla..     
      // Fire a propertychange event
      m_Support.firePropertyChange("", null, null);
  }

Answer 1

This seems kind of a strange way of doing things... but maybe I misunderstand what you are trying to do.
Here's what I think you are trying to do:
Read a file in a worker thread
While the worker thread is running, send update notifications to GUI objects in the Swing GUI thread.
Is that correct?
If so, then all you have to do is start the worker thread from the Swing GUI thread, then have the worker thread send periodic notifications to the GUI object - let's say in a method called textContentsChanged().
In textContentsChanged, you would then wrap up the notification into a simple Runnable object, and pass it in to invokeAndWait().
Is that what you are trying to do??
- K