I ran into this issue a few months ago, and discussed it in #java on Slack. The problem is that the application launch script inside the WOA bundle does some magic on all the arguments to get them into the right place on the eventual command line invocation. There are two issues: (a) --add-exports needs to appear before the Java class name on the command line; but (b) the launch script pre-dates the existence of any arguments that look like that, and hence doesn't move it. So it's appearing on the command line after the class name, and has no effect.

There's an easy fix, but you need to be using Maven to build: wolifecycle-maven-plugin 2.5 will add options like this to the *ClassPath.txt files, where they will be honoured on launch. You can specify them in build.properties.