This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Which two statements are true only when implementing rich client applications, and NOT when
implementing web browser-based clients that support only HTML? (Choose two.)
A. Information can be sent to the client by the server, without client polling.
B. Information can be encrypted prior to delivering it to the client and decrypted when received
to the client.
C. Information can be compressed prior to delivering it to the client and decompressed when
received to the client.
D. Information can be delivered to the client incrementally, without requiring that the server
deliver all the information to be presented to the client on each update.
Answer: A, D
I think none of the answer is right. As all 4 options are possible with HTML clients. Anybody can explain above answer?
"A" is correct because in the case of browser based HTML clients (thin clients), information CANNOT be pushed without client polling i.e. without client making a GET / POST request. Usually browser based client
is PULL System, meaning clients request information from the server. In the other case of thick clients, say applets, server can PUSH data to the Rich Client based on state changes in the model. In the latter case,
applets or rich clients didn't make a request for info, but yet server data gets PUSHED. This is usually done using the technique similar to observer pattern.
model.registerObserver(view) ---- This would cause the view to be updated when the model changes internally.
I think D is correct because in the case of, say AJAX based rich clients, server can send incremental data using JSON to update just a grid in the UI upon client requests without fully reloading the page. Whereas with HTML,
the entire page may need to be reloaded