Why can i not get reference to an observable list after using the .getText() method

So i've been playing around with javaFx and FXML and i keep running into a problem where i get errors when using a conditional statement with something like a .getText() method and trying to reference an FXML variable and its Items/children from within the bounds of this.

Take for example:

 Public Void checkTextField(TextField txt, AnchorPane pane){
   //#1
   system.out.println(pane.getItems());

   if(txt.getText() != null && !txt.getText().isEmpty())
   //#2
   system.out.println(pane.getItems());
 }

In this example #1 always works for me and will print out a list of what i've got in my pane (Or any container for that matter), whereas with #2 i always seem to get a NullPointerException and a InvocationTargetException if anyone knows why this could be, it would be great to find out what i'm doing wrong here or what i could add to make it work

cheers