Keeping fields around when you cache prepared-statements can really
become a drag, especially for large BLOBs and Strings.

Here's my suggestion. Current FBPreparedStatement looks like this:

public void clearParameters() throws SQLException {
for (int i = 0; i < isParamSet.length; i++)
isParamSet[i] = false;
}

I think it would work if you did something like this:

public void clearParameters() throws SQLException {
for (int i = 0; i < isParamSet.length; i++) {
field[i].setObject( null ); // free data
isParamSet[i] = false;
}

Then, in my CachedPreparedStatment#close method, I can just call
#clearParmaters to reclaim storage and make object available for garbage
collecting.