public static void setProperties(String subdomain, Map<String, String> propertyMap) {
        MUCServiceProperties properties = propertyMaps.get(subdomain);
        if (properties == null) {
            properties = new MUCServiceProperties(subdomain);
        }
        properties.putAll(propertyMap);
        propertyMaps.put(subdomain, properties);
    }
Sets multiple Jive properties at once. If a property doesn't already exists, a new
one will be created.

@param subdomain the subdomain of the service to set properties for
@param propertyMap a map of properties, keyed on property name.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/spi/MUCPersistenceManager.java