This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
I thinkg I am not good at Thread at present. The LockManager in DB Layer take charge of making present thread waiting for other client unlock and wakeing up all the sleeping thread when present client unlock. I am not sure whether LockManager should extend Thread. If not needed here, then the following form to use wait and notifyAll is correct or incorrect.
All of us feel more or less 'lost' at the beginning of the asignment. But have this in mind: to become a SCJD you must dominate multithreading. Begin being good at it. You will save time and headache.
I am not sure whether LockManager should extend Thread
Why aren't you sure? Do you want your lockManager instances starting concurrent executions?
If not needed here, then the following form to use wait and notifyAll is correct or incorrect.
I know many people here is not english speaker. Like me and likely like you. But IMHO this is the typical example of how a question must not be posted in a forum . Or maybe it's not a question, it's a big truth : "the following form is correct or incorrect"