jpackage ROOTDIR variable in a Windows bat file

[Michael Hall]

I am trying to come up with a simple Windows bat file execution of jpackage. I would like to use the builtin ROOTDIR variable. How should this be done?
Not very familiar with Windows.

This 
-Djava.security.policy=$ROOTDIR\app\all.policy
Gets
Error: Invalid Option: [-Djava.security.policy=$ROOTDIR\app\all.policy]

This 
-Djava.security.policy=%ROOTDIR%\app\all.policy
Gets this 
 Error: Invalid Option: [-Djava.security.policy=\app\all.policy]

These are included in the —java-options parameter.

This thread seems to end up indicating that $ROOTDIR should work on windows 
https://mail.openjdk.java.net/pipermail/core-libs-dev/2019-November/063361.html <https://mail.openjdk.java.net/pipermail/core-libs-dev/2019-November/063361.html>
Although it is for finding the runtime and not included in —java-options