> I absolutely don't understand what specifying a table to reserve in
> TPB means (don't even know what TPB is...)

TPB - Transaction Parameter Buffer, more info you will find in "API
Reference" for InterBase 6.0 (so-called, old documentation).

> Do I need that? :)

In theory - yes.

> I'm a never draining well of questions:
> Does transaction serializable throw an exception or waits until the
> lock releases?

Depends on the TPB. IIRC in default TPB mapping it will wait. You can
configure it to get an exception.

> If it throws an exception, how can I tell from that exception (in
> java), that it's not a consistensy error, just some transaction
> isolation thingamijig?

You have to find the appropriate error code (best would be to reproduce
exactly that error condition and save the SQLException.getErrorCode() value)

Roman