How to receive information on control elements within a Java application?

You don't really have a lot of control over which screen events Captivate can "hear".

If you know the exact screen object and event names in the Java app then you could perhaps try tweaking the text in the RDL files in your Captivate install directory.  (Look at CaptureTextTemplates_English.rdl as an example.)  But I've not found anyone that has had much success this way.

Your best solution is just to use manual captures by hitting the relevant key you have set up in Captivate Preferences for manual capture.