"deprecated" means that the feature you are using (the debug field in the Priority class, in your case) is no longer the preferred way of accessing this information and at some future time might no longer be allowed, but at this time the feature still works. As an example, there are many things that have been deprecated since Java 1.1 that still work.
Your choices are:
a) ignore the warning
b) change you code to use the preferred mechanisms (the documentation for the debug field should say what replaced it)