SAPUI5 oModel.getJSON() isn't working when I use a JSON file as origin

I created my Model using a JSON file.

var oModel =new sap.ui.model.json.JSONModel( jsonFileUrl );//JSON from file

It worked and the element was populated as I wanted. But after this, when I tried to use oModel.getJSON() to get the JSON data it didn't work.

If I use an variable with the same content as the file, it works!

You can check the full test that I created:
https://googledrive.com/host/0B2gJUv6a_V1dYnNSV0ZsTFhxazg/index.html

Is there anybody to help me to understand what on Earth is happening here?