How to retrieve Image Ressource location on the sever

Vaadin 6 / 7 / 8
1

Hi all,

I need to retrieve the url of used ressources in my vaadin 7 web application, in my case the ressource is an image which can be located in
VAADIN/themes/themename/img
 folder or it can be founded in a jar file.

So the method i want to write has this signature :

/**
* Returns the URL for an image described with its name
*/
public String getURL(String image) { ... }

Any idea will be appreciated,
Many thanks