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No way to throw DuplicateKeyException

Jianping Wang
Ranch Hand

Joined: May 29, 2010
Posts: 60

I don't know on what condition will the DuplicateKeyException be thrown. because this method is synchronized and the recNo is allocated inside this method.

SCJP 6 with 93%
Oracle Database SQL Expert with 98%
Martin Krischik

Joined: Apr 29, 2010
Posts: 23

May I quote the the instruction.html to you (no ridicule, I mean it as an honest hint):

This document deliberately leaves some issues unspecified, and some problems unraised. Your ability to think through these issues, in the face of realistically imperfect specifications, and come to a tenable solution is something upon which you are being graded.

My solution is not the raise DuplicateKeyException at all. I have not yet passed so I might be wrong.


Roel De Nijs

Joined: Jul 19, 2004
Posts: 8358

I didn't throw a DuplicateKeyException from create method, because there is simply no appropriate key. In a hotel there can be more than 1 room available for the same night with the same characteristics. So when room numbers will be added to the database file, it makes sense to throw the DuplicateKeyException, but at this moment it doesn't. Of course I documented this decision in choices.txt

SCJA, SCJP (1.4 | 5.0 | 6.0), SCJD
I agree. Here's the link:
subject: No way to throw DuplicateKeyException
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