switching from 7.4.1 to 8.0-311 jdbc driver

Hi,

I am proposing a change to the newer 8.0 jdbc driver - it seems to clear
up some odd things I was seeing logged heavily:

2005-04-19 16:43:03 LOG:  00000: duration: 0.246 ms
LOCATION:  exec_simple_query, postgres.c:960
2005-04-19 16:43:03 LOG:  00000: statement: rollback; begin;
LOCATION:  pg_parse_query, postgres.c:464

My question is - are there any "gotchas" I need to look out for -
changes in behavior, etc, that might cause problems with this switch?
The java application makes use of autocommit() quite a bit.

I am running postgresql 7.4.2.

Thanks,

Dennis