Any examples of how to use EventListener interfaces to create interactive documents ...

Even though libreoffice is being actively rid of java:

What features absolutely require Java?

Is there any plan to ditch Java in the future and use only C/C++ code?

java’s EventListener interface is cool. Imagine you have some interactive document in which when you hover the mouse over the word “red” a picture next to it becomes red.

How could you do that with C or C++?

If you cannot, how could you make java do it in a LO document?