In SSJS, we can get SessionAsSigner. But when we are in pure Java -  for exemple when developing a custom REST Service (a custom RestServiceEngine class) - how do we get Session As Signer ? 
    - I tried to use the extlibutil getSessionAsSigner, the NotesContext.GetSessionAsSigner... all return null
    - I tried to create a session using NotesFactory.createsession (...) (assuming I've the userid/password I want to use), but I get an exception "Cannot create a session from an agent".
     
    So, finally, my question is : in Java (not SSJS), on the XPages runtime, how can I execute code with other privilege than the current user session.
     
    Thanks