Java 1.6 sbt test Oracle JDK only?

Clone snowplow successfully and running sbt test follows.
Is this correct Oracle JDK only? Wow. I use sdkman useless here.

09:01 $ sbt test

The java installation you have is not up to date
requires at least version 1.6+, you have
version 11.0.2

Please go to http://www.java.com/getjava/ and download
a valid Java Runtime and install before running .