public UUID login(final String realmName, final String username, final String password) throws LoginException { final Realm realm = findRealm(realmName); if (realm == null) { throw new LoginException("No Tomcat realm available"); } final Principal principal = realm.authenticate(username, password); if (principal == null) { throw new CredentialNotFoundException(username); } final Subject subject = createSubject(realm, principal); return registerSubject(subject); }