void localPut(String key, String value) {
        properties.put(key, value);

        // Generate event.
        Map<String, Object> params = new HashMap<>();
        params.put("value", value);
        MUCServicePropertyEventDispatcher.dispatchEvent(subdomain, key, MUCServicePropertyEventDispatcher.EventType.property_set, params);
    }
Returns all property names as a Collection of String values.

@return all property names.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/spi/MUCServiceProperties.java