to override updateItem

*** Requirement ***
For ListView to show String is most basic practice.
ListView can show any Object by default toString().
However ever we want to show other property of certain Object with Persistence constraints, we need to call setCellFactory.
Parameter of setCellFactory will be a class implements Callback interface.
Callback interface defines a parameter and a return type.
By example, it can turn ListView to show Rectangle instead of String.
The return type of ListView is subclass of ListCell, the major method to override is updateItem.
Method updateItem is inherited from class javafx.scene.control.Cell.
There is no return for updateItem. It provides parameter String item. This should be the original data show on ListView.



JavaFX, simple TreeView

NetBeans 7.4
New Project >> JavaFX >> JavaFX Application
We have one button and one label. When click button, label shows “Hello World!”
Based on sample code from

Put them under
@FXML private void handleButtonAction(ActionEvent event)
, and modify some,