I was able to download the SparkJDBC42.jar from here:
Is this driver available through Maven somewhere?
Maven is not mentioned in the documentation here:
https://docs.databricks.com/integrations/bi/jdbc-odbc-bi.html
http://www.simba.com/wp-content/uploads/2014/12/Simba-JDBC-Driver-for-Spark-Install-Guide.pdf