We're using jTDS java version 1.2.5. It doesn't support multisubnet failover but it doesn't need to. Multisubnet failover can be handled on the SQL side (we're using SQL 2014), as long as the SQL server login you're using has it's SID number matched (and you're using the Listener name).

How to match the SID's

From the Primary (where the username should already exist under Security | Logins and should already be mapped correctly to user database(s):

select SUSER_SID('the_username');

From the Secondary (where the username DOES NOT exist under Security | Logins but DOES exist under user databases due to synchronization):

Take the Hex ID from the first command and use it below:

USE master

GO

CREATE LOGIN [the_username] WITH PASSWORD = 'whatever', SID = yourHexNumberNoQuotes, DEFAULT_DATABASE = [sameDefaultDB_as_PrimaryLogin], DEFAULT_LANGUAGE=[us_english], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF

GO

Go into Properties of the SQL Server username (Security | Logins) on BOTH servers and reset the passwords to match.