Yes, you can use the Runtime/Java API to add client instructions that match all of the things you can do in a microflow using the FeedbackHelper class.
Specifically, you’re looking for FeedbackHelper.addOpenFormFeedback().
Is there a reason why you would like to use a java action?
In the modeler you can give a page a URL and then you target the URL
mendix is SPA, so you may have to follow that way it works, and using deeplink for more advance configuration.