This is an example Play application that uses Java, and communicates with an in memory database using EBean.
The Github location for this project is:
https://github.com/playframework/play-java-ebean-example
Play documentation is here:
https://playframework.com/documentation/latest/Home
EBean is a Java ORM library that uses SQL:
https://www.playframework.com/documentation/latest/JavaEbean
and the documentation can be found here: