Some clarification required on few topics:
1) In most of the Application Servers apart from the Server jvm which is available there will be nodes of jvm which are mainly for batch processing. By using these nodes of jvm and using threads in them will solve the purpose of batching. Today I think most of the enterprise based applications do have Batching supported, for example startNodeManager in case of Weblogic Application Server and also these are available in other Application Servers as well. What are the benefits provided by new Batch processing in Java EE 7?
2) In case of WebSockets, How scale-able will the application be if it supports WebSocket at least in case of Glassfish 4? The way I understood is if there are 10,000 users connected to the server and opens the WebSocket request for conversation then there will be 10,000 HTTP upgrades to ws or wss requests are to be maintained. Will there be any issues if all the 10,000 users accessing the same information like in case of retrieving the latest Stock price of a commodity? Will it maintain any client specific conversations among two clients like chat application between two clients, in case of 10.000 users if every client is interacting with other but not all it may end with 5000 their specific information that has to be stored at the Server for all 10,000 users.
3) In case of Asynchronous Servlet, If a Client request spawning into a thread and waiting for an update from the Server then When there is an update from the Server will there be an another thread which will process the response for that Client. Is it like Server push the updates when available and those are sent to the registered Clients irrelevant of thread?
4) Second level Cache for JPA, Do it says to maintain good amount of RAM memory at the Application Server? Or will it be good if the memory is maintained in separate jvm on the same application server. Hardly remote invocation is better than database fetch.
Few suggestions for the Java EE Tutorial after every chapter if it is followed with few examples or their usages in some Use Cases is provided and followed with some Q&A like JavaSE follows it will be very grateful.
N. Naresh Kumar.