private Class getConverterClass() {
        if(Enum.class.isAssignableFrom(clazz)) {
            return Enum.class;
        } else {
            return clazz;
        }
    }
Returns the SystemProperty for the specified key

@param key the key for the property to fetch
@return The SystemProperty for that key, if any
xmppserver/src/main/java/org/jivesoftware/util/SystemProperty.java