This week's giveaway is in the Spring forum.
We're giving away four copies of liveProject: Protecting User Data with Spring Security and OAuth2 and have Laurentiu Spilca on-line!
See this thread for details.
Win a copy of liveProject: Protecting User Data with Spring Security and OAuth2 this week in the Spring forum!


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since Oct 28, 2005
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Recent posts by Macy

Anyone use Eclipse or MyEclipse? And good book recommend? I know Java, JSP, Servlet, EJB... But I want to learn to use Eclipse. Thanks!
14 years ago
Thanks for let me know about the open source projects. I'm looking at those site now. Thank you!
15 years ago
I'm in SF bayarea, CA USA.
15 years ago
Sorry, I'm not native American. What's open source project means? Just build any applications I like? Or that will be some requirements and guidelines I can follow just like the SCJD assignment?
15 years ago
How did you prepare for your exam? Did you use any exam simulators/free exams?
15 years ago
I need to gain immediate hands on java work experience. Volunteer and non-paid positions are OK.

Please send me an email at

15 years ago
I'm living in SF bayarea. I just got Oracle OCA, SCJP 1.4 & 5.0 and SCWCD in 2005; and SCBCD and SCJD in SCJD in 2006.

I don't have work experiences in java development but academic programming experiences, and I'm looking for a position to start. I'm a green card holder and relocation is OK for me.

If you have any job openings, please give me an email.

Thank you!
15 years ago
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
15 years ago
Yes, that's normal. You will see it only when your grade is returned. Mine takes 23 days after I took the essay. Sit back and relax.

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
15 years ago
Just passed an hour ago. :roll:
Now wait for the results for me SCJD. Hopefully I can get a technical job soon...
15 years ago
Network Approaches:
Your choice of RMI or serialized objects will not affect your grade, but no other approach is acceptable. In either case, the program must allow the user to specify the location of the database, and it must also accept an indication that a local database is to be used, in which case, the networking must be bypassed entirely.

Target Platform and Execution
java -jar <path_and_filename> [<mode>]
Your programs must not require use of command line arguments other than the single mode flag, which muxt be supported. Your programs must not require use of command line property specifications. All configuration must be done via a GUI, and must be persistent between runs of the program. Such configuration information must be stored in a file called which must be located in the current working directory.

Q1: I read some previous forums.
Standalone mode: save the location of the data file.
Network server mode: save the location of the data file and the port number.
Network client mode: save the host and the port number.
Is it correct?

Q2 When first time running the standalone mode, or the network server mode; the user need to specific the location of the data file and the program will save in
When running second time, I can load the previous setting. Should I start the application automatically or still give the user an option to change it and click the "start" button?

Q3 If I called the application from c:/folder_a/ and c:/folder_b/, I will have in both folders since this file save in current working directory?

Q4 Once the application is running, these properties cannot be changed until stop and restarting?

I just want to double check and make sure I understand the requirement correctly. Thanks for your help.
In my program, I use the following:

Name only:
criteria[0] = "fred";
criteria[1] = ""; (Any in my GUI)

Location only:
criteria[0] = ""; (Any in my GUI)
criteria[1] = "atlantis";

Name & Location:
criteria[0] = "fred";
criteria[1] = "atlantis";

each values use for one column. First value for first column, ... null values will return all records.
I never heard POJO, I would like to find out more about it.
Thank you so much!!! I don't have a carriage return at the end of the line.
It works fine now.