Hi Omar,
Welcome to this forum and JavaRanch!
(OK, it looks inverted and it's not my normal way of welcoming people here, but I wanted a
slight different phrasing than Andrew in this thread
).
Andrew:
As for locking client side / server side, you may be interested in reading the (long) thread "Should lock methods be callable by the client" which will probably give you more arguments both for and against locking either way than you probably wanted to read .
I totally agree with Andrew.
I'd just want to add:
that in the meantime published scores have proven than both solutions (badly called "2-tiers" vs "3-tiers" in that thread) are equally accepted by SUN; that I like your arguments under 2) above, but that it's personal. Best regards,
Phil.