Hi Shlomo,
When you do order your assignment, you will find that it requires you to use a version of the JDK that has not been superseeded by a production version of the JDK by 18 months. Right now that means that the only JDK that you are allowed to use is JDK 5.
I was wondering if we can use the new features from 5.0 such as R/W Lock?
The statement from Sun is that the instructions that
you download are the definitive guide to what is allowed or not allowed. Since you could download some new instructions that have not yet been discussed, it is not possible to guarantee that you will be allowed to use R/W locks, however currently we know of 3 assignments, each with multiple versions, and none of the known versions forbid R/W locks. So you can almost certainly use R/W locks.
Also, if we synch the DB and allow for only serial access, is that acceptable solution?
Maybe.

It all depends on how much you limit access. There is a requirement to allow concurrent access to the networked server, and a bad solution would result in failing to meet that requirement. On the other hand, you do have to implement all the standard database CRUD methods (Create, Read, Update, Delete), so at some point you will have to have synchronization to ensure that your data file does not become corrupt. Your challenge Shlomo, should you choose to accept it, is working out how to balance these two conflicting issues.
Regards, Andrew