Just in case any body else comes across this issue (and thanks to Brian for the answer) using the example DB and testing the @jdbcUpdate you may see an Array out of bounds message.
The current fix is to add a null parameter on the end. For example in the Xpage JDBC_AtFunction in the Update Boston button I changed it from
this :
var c = @JdbcUpdate(“derby1”,“users”,v,“id=?“,id)
to:
var c = @JdbcUpdate(“derby1”,“users”,v,“id=?“,id,null)

I have been informed the last parm should be optional , but it is not presently.