Torsten Krah I am finding a lot of references online that claim that the Oracle JDBC driver does not support calling Oracle procs/functions that define PL/SQL BOOLEAN arguments/returns via CallableStatement. Since you seem to have a working Oracle set up already and a vested interest in seeing this resolved, would you be able to investigate that? Try to execute dbms_stats.GATHER_TABLE_STATS yourself directly through java.sql.CallableStatement and see if you can find the magic incantation needed to get that to work.