vacuum

hello all,

I try to call VACUUM ANALYZE through a PreparedStatement. As the logfile only 
lists debug messages for VACUUM that I start in psql I suspect that the the 
VACUUM in my java app is never called.

Prepared Statement prepVacuumAnalyze = con.prepareStatement( "VACUUM ANALYZE" 
);
prepVacuumAnalyze.execute();
con.commit(); // auto commit is off

Is it not possible to call such SQL commands in jdbc?

thank you
Chantal