I spoke to my Sun representative here in Spain and she told me that Sun doesn't allow exam revievews!
The marking is done in three phases. First, software checks that overall structure and nomenclature conform to specification. Second the examiner runs the code ensuring that it functions correctly through the specified operations. If any automatic failures are noted at this stage, the marking process terminates and the assignment is failed.
Server (maximum = 53): 23
Major point loss for record-locking mechanism. Operation is fine when trying to lock a record that is already locked. But when trying to lock a single record at a time when the entire data base is globally locked, the code throws an exception rather than blocking.
If I were you, I would contact Sun through the email address in your instructions file. Give them enough details so that they can look up your file, and ask them to either review your case, or to provide you with the examiner's comments on why they chose to give you zero marks.
Locking was the problem, but I tested it quite well before submition, using JUnit, different users, manual locking, so I'm pretty confident with it.
Note that while the unit of time of the return value is a millisecond, the granularity of the value depends on the underlying operating system and may be larger. For example, many operating systems measure time in units of tens of milliseconds.