[netcdf-java] ThreddsDatasetChooser

Hello All,


I was hoping someone out there had some experience implementing the
ThreddsDatasetChooser component and would be willing to help me out a
bit.  I've made a very simple test class to get the
ThreddsDatasetChooser up and running.  The class is at the end of this
email.  I'm able to display the dialog without much trouble, but I am
unable to make it connect to a catalog.  When I enter a catalog URL into
the combobox and click "Connect", a progress dialog comes up after a few
seconds and tells me that it's "opening the catalog"...but after about
20 seconds or so, the dialog goes away and nothing else happens.  I also
get the following exception in the output pane of my IDE:


Exception in thread "Thread-2" java.lang.NullPointerException


        at java.lang.Thread.run(Thread.java:613)


Can anyone help me out and let me know what I'm not doing or doing


Thanks in advance,




import java.io.IOException;

import javax.swing.*;

import thredds.catalog.ui.ThreddsDatasetChooser;

import ucar.util.prefs.PreferencesExt;

import ucar.util.prefs.XMLStore;




 * @author asamac


public class Browse {



     * Creates a new instance of Browse


    public Browse() {




    private static void createAndShowGUI(){

        JFrame frame = new JFrame("Thredds Catalog Browser");

        frame.setSize(800, 600);



        JTabbedPane tabPane = new JTabbedPane();


        XMLStore store = null;

        try {

            store = XMLStore.createFromFile("xmlStore.xml", null);

        } catch (IOException ex) {



        PreferencesExt prefs = store.getPreferences();

        System.err.println("prefs instantiated");

        ThreddsDatasetChooser datasetChooser = new
ThreddsDatasetChooser(prefs, tabPane, frame, true, true);

        System.err.println("tdc instantiated");

        datasetChooser.addPropertyChangeListener( new
java.beans.PropertyChangeListener() {

          public void propertyChange( java.beans.PropertyChangeEvent e)

             if (e.getPropertyName().equals("Dataset")) {

                 System.err.println("single dataset");

             }else if (e.getPropertyName().equals("Datasets")){

                 System.err.println("multiple datasets");

             }else if (e.getPropertyName().equals("InvAccess")){











     * @param args the command line arguments


    public static void main(String[] args) {

        // TODO code application logic here

        javax.swing.SwingUtilities.invokeLater(new Runnable() {

            public void run() {










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