Stuff

    public void deleteABookmark() {       if (tree != null) {         if(tree.getLastSelectedPathComponent() != null)            treeModel.removeNodeFromParent((MutableTreeNode)tree.getLastSelectedPathComponent());                 else return;       }       else return;    }    public void valueChanged(TreeSelectionEvent e)  {    	    	try {     	 if (tree == null)      		 return;     	 else {     		     	  if(tree.getLastSelectedPathComponent() != null) {            BufferedReader in = new BufferedReader(new FileReader("bookmarks/" + tree.getLastSelectedPathComponent().toString()));            String s = in.readLine();                   if(s!=null) {               main.changeUrl(s);               main.addToHistory(s);               main.changeHistoryIndex();               main.checkButtons();             }    	 }    	   else         	 JOptionPane.showMessageDialog(main, "That file is not a valid Bookmark file.","Invalid bookmark file",JOptionPane.ERROR_MESSAGE);     	     	 }       	}  catch (IOException exc) {          	  JOptionPane.showMessageDialog(main,"That bookmark doesn't appear to exist.","Bookmark does not exist.",JOptionPane.ERROR_MESSAGE);           }   }