Hi Zhou,
think about how your gui behaves with long running (say, 2 seconds) method calls on the server - if you call those methods from the gui thread, the client will look frozen to the user. Just for fun, I've inserted a sleep into the criteriaFind() method, and it felt bad
Maybe with the 24 records in the assignment this all is no problem, but I always tried to keep a real environment in mind.
Greetings,
Ralf