+1. I'm not 100% sure how often people will face the first use case, but I already had an issue related with it. In Apache MINA, a user is not allowed to create a configuration object but only get the current configuration and set its properties (e.g. service.getConfig().setReadBufferSize(1024)) The reason we don't allow a user to create a configuration object is because its default values differ between a server-side application and a client-side application and we don't want users to spend their time to specify it's a server side configuration or a client side configuration, which is often error-prone and leads to unnecessarily crowded mailing list. :) So, I think this kind of case, that an API provider wants to restrict the creation of a certain object but the provider is fine with the modification of its properties, will happen pretty often. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4105394#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...