Você precisará reescrever ou lançar a expressão.
PreparedStatement stmt = conn.prepareStatement(
"INSERT INTO Event (EventNum, EventName, startHour, endHour, startMin, endMin, startDate, endDate, State, depName)
VALUES (?, ?, ?, ?, ?, ?, ?::date, ?::date, ?::status, ?)");
Motionless Millipede