FXML: forget namespace throw NullPointerException

In a little piece of include fxml, I get a NullPointerException.

Here is the fxml (include in another fxml)

<TableView fx:id="stocksList" >
<columns>
<TableColumn text="Titre" prefWidth="125">
<cellValueFactory>
<PropertyValueFactory property="test" />
</cellValueFactory>
</TableColumn>
</columns>
</TableView>

I forgot the namespace xmlns:fx="http://javafx.com/fxml" and I get this error:

Caused by: java.lang.NullPointerException
at javafx.fxml.FXMLLoader.logException(FXMLLoader.java:2211)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2030)
at javafx.fxml.FXMLLoader$IncludeElement.constructValue(FXMLLoader.java:936)
at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:565)
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2314)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2131)

The exception gives no direction about the problem and it's very difficult to find what is wrong.
Maybe this problem must be check before.