private void loadProperties() {
        if (resourcePath == null || resourcePath.length() == 0) {
            throw new IllegalStateException("The resourcePath property is not set.  "
                    + "It must be set prior to this realm being initialized.");
        }

        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("Loading user security information from file [" + resourcePath + "]...");
        }

        Properties properties = loadProperties(resourcePath);
        createRealmEntitiesFromProperties(properties);
    }
Destroy reload scheduler if one exists.
core/src/main/java/org/apache/shiro/realm/text/PropertiesRealm.java