Change effective on 10 August 2016
Heroku’s support for Java, Scala, Clojure and Groovy applications now sets the
$JDBC_DATABASE_URL environment variable for the JawsDB Maria add-on when it has been added to an app.
For more information on the Maria add-on, see JawsDB Maria in Heroku Elements. For more information on connecting to a database with JDBC, see the Dev Center guide for Connecting to Relational Databases on Heroku with Java.