The jtds 1.2.5 driver reports the following information about a varchar(max) column (compared with inet's and microsoft's drivers):
inet | VARCHAR | varchar | java.lang.String | LONGVARCHAR | LONGVARCHAR
ms | LONGVARCHAR | varchar | java.lang.String | LONGVARCHAR | LONGVARCHAR
jdts | CLOB | text | java.sql.Clob | CLOB | LONGVARCHAR
The other drivers are consistent (except that inet retains backwards compatibility with the general result set type). Jtds reports the column as clob and text, except when getting the "SQL_DATA_TYPE" metadata from the database column metadata.
Code for generating the table attached.