}
                return ssn.acquire();
            }
            if (log.isTraceEnabled()) {
                log.trace("Existing session " + ssn + " does not match " + tf.getCredentials());
            }
        }

        /* logoff old sessions */
        if (tf.getConfig().getSessionTimeout() > 0 && this.sessionExpiration < (now = System.currentTimeMillis())) {