public void destroy() {
        try {
            if (scheduler != null) {
                scheduler.shutdown();
            }
        } catch (Exception e) {
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("Unable to cleanly shutdown Scheduler.  Ignoring (shutting down)...", e);
            }
        } finally {
            scheduler = null;
        }
    }
Destroy reload scheduler if one exists.
core/src/main/java/org/apache/shiro/realm/text/PropertiesRealm.java