For SQL Server 2012 you will need to use a jTDS 1.3.x driver instead: https://sourceforge.net/projects/jtds/
As for SQL Server 2016, I am not sure. In terms of SQL Developer, the last word I can find (re: SQL Server 2014) is
while it looks like the jTDS driver currently does not list support for 2016... jTDS JDBC Driver
Thank you very much for your answer. jTDS works against SQL Server 2012, and also SQL Server 2016 (not tested extensively, but we can connect and browse data). Logon works via Windows Auth works. Connection to specific instance requires, that you find out which port that the instance listens on.