I have some questions about 'failover' and 'hot deployment' on several J2EE platforms, any advice or hints will be highly appreciated, thanks a lot!
1. Some vendors, such as IBM websphere, have fufil the "stateful session failover" and "HTTP session failover", so we can easily use those functions just as do a little setting work in container level. It seems that those functions are not a part of J2EE standards,but just the extension function supplied only by different vendors (correct me if I am wrong). I just want to know how different J2EE platforms, such as Websphere, Weblogic or Jboss, realize the 'failover' capability, do they fufil this function in similar fashion? is there any standard on this 'failover' issue? my problem is, if we achieve 'failover' in contaniner level, will we have problem when we transfor from one platform to another platform? Such as from websphere to weblogic. And is there a potential for 'Failover' be a standard of J2EE?
2. Some vendors also provide the "hot deployment" function, We know that this capability is not a native part of J2EE, but just the extension function provided only by different vendors (also correct me if I am wrong). I just want to know what is the difficulty to achieve 'hot deployment', why in some case, when we deploy a new application to the server, we must restart the server.
Thanks for your reading my long questions, as a newbie and have emergency task to finish, I really need your help, thanks for your response!