private static final void loadExtModules() throws Exception {
        ClassLoader extClassLoader = ViewProperties.loadExtClass();
        Vector<String> moduleListTreeView = ViewProperties.getTreeViewList();
        Vector<String> moduleListImageView = ViewProperties.getImageViewList();

        if (extClassLoader == null || moduleListTreeView == null || moduleListImageView == null) return;

        String[] extTreeViews = { "ext.erdc.TreeViewERDC", "ext.npoess.TreeViewNPOESS" };

        String[] extImageViews = { "ext.erdc.ImageViewERDC" };

        for (int i = 0; i < extTreeViews.length; i++) {
            if (!moduleListTreeView.contains(extTreeViews[i])) {
                try {
                    extClassLoader.loadClass(extTreeViews[i]); // make sure the
                    // class exists
                    moduleListTreeView.add(extTreeViews[i]);
                }
                catch (Exception ex) {
                    continue;
                }
            }
        }

        for (int i = 0; i < extImageViews.length; i++) {
            if (!moduleListImageView.contains(extImageViews[i])) {
                try {
                    extClassLoader.loadClass(extImageViews[i]); // make sure the
                    // class exists
                    moduleListImageView.add(extImageViews[i]);
                }
                catch (Exception ex) {
                    continue;
                }
            }
        }
    }