@cedric: there are still problems:
Problem 1: application.properties from "pro" flavor is in the root of built war instead of WEB-INF/classes (there is no use from it there). While application.properties in war:WEB-INF/classes is still taken from the default resources, but not from "pro" flavor.
Problem 2: Product.class in WEB-INF/classes/com/example is also taken from the default folder, not from "pro"