Just want to say thank you so much!!!

[Macy]

I can't believe that I got 388/400 from my SCJD. The only section I got points off is the GUI.

Thanks everyone who leave a post / response on this forum. It's a big help. Thank you! Thank you!! Thank you!!!



General Con: 100 100
Documentation: 70 70
OOD: 30 30
GUI: 40 28
Locking: 80 80
Data Store: 40 40
Network Server 40 40

[Bob Nedwor]

Good Work, Macy! Congratulations.

[Andrew Monkhouse]

Awesome score Macy - congratulations

[Andrew Monkhouse]

Moved to Sun Certification Results forum.

[Mikalai Zaikin]

Macy , congratulations !!!

[Ronald Wouters]

Macy, great score, almost beat Ken Krebs (faq, 389/400).

By the way, could you tell me what you did to avoid the dredded 44/80 locking score ?

Regards,
Ronald Wouters

[Sam Codean]

Congratulations!! Macy You deserve an Applause
I would be glad if you could shed some light on Locking.

[Bharat Roy]

[Macy]

I implemented a separate lock manager class that allows Insert Row Locking
(IRL) so that if two or more clients attempt to perform the sequence
lock-read/modify/write-unlock concurrently, both modification attempts
will be handled correctly. The lock manager class provides consistent
and concurrent access to data in a multi-user environment (RMI). Because
IRL is necessary only in remote mode, not in local mode, it makes better
sense to implement it as a separate lock manager class. Locks prevent
simultaneous updates of the same row of data. With a separate lock
manager, only one user at a time can update/create/delete a row of data.
So while one user is booking a subcontractor, another user cannot modify
the same row record. Without a good lock manager, users could overwrite
each other booking, giving the impression that someone can book the
same contractor to more than one person.

The row is locked by a given client cookie. Since I'm using RMI remote
access, the user will be assigned a random thread each time when it
accesses the server. The application is not guarantee on the same thread
so thread reference is not able to use. I created a client cookie class
to generate a cookie automatically when the user starts the client's
applications. The odds is 2 to the power 31 is nearly 0. It is impossible
for two clients assigned the same cookie. The responsibility for record
locking is kept in the DataLockManager. Always make sure the specific
record is lock free before locking to prevent dead lock issue. If the
specific is locked by another client, it will wait until the lock is
released.

[wise owen]

Congratulations!!