- keep one PreparedStatement around for every possible number of
elements in the parameter list => in (?), in (?, ?). You could create a
class that creates (and caches) the PreparedStatements on the fly
- create a PreparedStatement with many parameters and fill unused
parameters with setNull ()
- try batch execution. I know of at least one database where sending
multiple parameter sets for a SELECT results in the UNION. But this
would work only for 'level in (?)', not for 'level not in (?)'.

Daniel

Probably the easiest solution in Java is to create a statement
String in a StringBuffer and append the same number of placeholders
(?) as list elements, convert to a String, create a PreparedStatement
and fill in the placeholders. Eg:

StringBuffer sb = new StringBuffer(
 "Select ID from Users where level in (?");
int n = list.size();
for(int i = 1; i < n; i++) {
 sb.append(",?");
}
PreparedStatement ps = con.prepareStatement(sb.toString());
for(int i = 0; i < n; i++) {
 ps.setObject(i, list.get(i));
}
ResultSet rs = ps.executeQuery();

Hope this helps.

Chuck