JDBC updateNull method returns null pointer exception

I've been working on some application code (written in C++ and calling
JDBC methods via JNI) that makes extensive use of updateable result
sets. I've done a couple of driver builds from the most current versions
of the source from the CVS repository and everything seems to work quite
well with one exception: calls to the 'updateNull' method(s) generate
java.lang.NullPointerException faults. I have only a basic working
knowledge of the Java language but the likely culprit seems to be the
'null' value passed to the 'put' method of the 'updateValues' Hashtable
object.

My question is: What should the actual implementation be to replace this
stub? Does anyone have any suggestions regarding what object should
really be instantiated to map to a NULL table column value for the
parameterized SQL statement constructed in the 'updateRow' method?

I'm an experienced systems programmer but relative novice in this
particular area (in fact, this is my first ever post to a public
newsgroup ... it's kind of exciting). I'm hoping one of the recent JDBC
developers/maintainers will be able to help with this issue.

Thanks in advance,

Sean T. Gates
Signiant Corporation