When I run sm2 -diagnostic I see JAVA: NOT OK: unable to find java version even though I think it ought to work.

I think the problem is that this regex is looking for 3 numbers separated by .s but that doesn't appear in the output on my system:

$ $JAVA_HOME/bin/java -version
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment AdoptOpenJDK (build 11+28)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11+28, mixed mode)