Sounds interesting!
It is not possible to access action triggers from Java. However, you can assign a microflow to each action trigger which executes another microflow (via Java) based on a microflow name retrieved from a configuration object. In this way you can configure the connections between action triggers and microflows at runtime!
In more detail:
Core.execute(microflow name, ...)
.By changing the configuration object in the web client you can change the microflow which is executed when clicking the action trigger. At runtime!