Correct it is a stupid question on two counts:
1) You should ask a lawyer!!!!!!!!!!! I cannot stress this enough.
2) Your question is better targetted at the MySQL licensing department.
IANAL (I am not a lawyer) and you haven't paid me for legal advice
so you should not depend on the rest of this comment.
NOT LEGAL ADVISE
The LGPL/GPL is about linking and distribution.
There are no restrictions if you just use the software.
JBoss is LGPL and is designed to work with many databases.
The default distribution of JBoss only includes HSQLDB which has a sort of BSD style
If *you* link GPL code with LGPL and *distribute* it, the whole distribution becomes GPL.
If you want to distribute your application, JBoss and the MySQL driver
the whole thing MUST be GPL, including your application.
If you want to distribute your application and JBoss and get your customer
to link/choose to run it with MySQL, JBoss is still LGPL and you
can choose whatever license you like for your application.