Change effective on 20 March 2019
Heroku’s support for Java, Scala, Clojure, and Gradle now includes support for OpenJDK version 12. To use this version of the JDK, create a
system.properties file in your application with the following contents:
After your next deployment, Heroku will install and run your app with OpenJDK 12. For more information, see the article on Heroku Support for Java in the Dev Center. For more information on JDK 12, see the official OpenJDK documentation.