DefaultMutableTreeNode top;
DefaultMutableTreeNode category = null;
DefaultMutableTreeNode book = null;
if(obj.getClass()==adt.class) {
adt o = (adt)obj;
top = new DefaultMutableTreeNode(new MenueEntry(FileName, 0, this, pack));
// files
category = new DefaultMutableTreeNode(new MenueEntry("Files", 1, this, folder));
top.add(category);