jdbc datatype API/Reference

I am getting an exception:

org.hibernate.MappingException: No Dialect mapping for JDBC type: -9

I found a list of JDBC Data type here Apache DB Project . How do I find out "-9" maps to one of the data types listed? From googling, people seem to say -9 represents nvarchar, but is there an authoritative source?

http://download.oracle.com/javase/6/docs/api/constant-values.html#java.sql.Types.REAL

from the javadocs themselves