LocalInvocationHelper enables direct Java calls from WS-GRAM
to RFT without going the WS way. Therefore a MessageContext
is created with all information a service (in this case RFT)
needs. Part of this is a subject.
However: i did an error in the subject creation by adding the
DN of the caller by
subject.getPrincipals().add(new UserNamePrincipal(userSubject));
But it must be
subject.getPrincipals().add(new GlobusPrincipal(userSubject));

RFT gets along with this error (that's why it didn't show up),
but it's technically wrong. If the change is done also a local
username must be added, because RFT requires it (funnily that
works currently too). For this the UserNamePrincipal must be
used:
subject.getPrincipals().add(new UserNamePrincipal(localUserId));

This requires an interface change in the LocalInvocationHelper,
but since it's currently for WS_GRAM internal use only that's ok.
Plans are to move that functionality to Core, maybe for 4.2.
Probably some issues that may currently not be perfect get
improved then.