Returns a single Subject's principals retrieved from all configured Realms as a List, or an empty List if
there are not any principals.
<p/>
Note that this will return an empty List if the 'owning' subject has not yet logged in.
@return a single Subject's principals retrieved from all configured Realms as a List.
Returns a single Subject's principals retrieved from all configured Realms as a List, or an empty List if there are not any principals. <p/> Note that this will return an empty List if the 'owning' subject has not yet logged in.
@return a single Subject's principals retrieved from all configured Realms as a List.