Work with active Intellij files programatically (java)

Hi, I am looking for java solution for the following scenario.

I need to get titles of all active files in Intellij IDE (also its content if possible) in my java application. Firstly, my java application run Intellij IDE (runtime.exec()). Later, I need to list active files of this Intellij instance.

I found com.intellij.openapi library for creating plugins. But it doesnt seem to be a proper solution. I dont want to use plugin.xml, just library.

Do you have some experience with this topic?

Is there a way to initialize EditorManager()? Or, is it possible to cast java.lang.process to EditorManager() instance?

Thank you.