In eclipse, while debugging, how do I access the interactive-top-level (a.ka. the "display console")?

You can use the Display view to execute arbitrary code, access it via:

window->Show View->Display

then type the code you want to execute (you can use CTRL+SPACE for autocomplete).

to execute the code, select it then:

CTRL+SHIFT+D

That should execute the code based on the breakpoint you've hit.

Note: As of 2018, Display View has been renamed to Debug Shell View.

Eclipse has it indeed. Window->Show View->Interactive Console. Note that you can also execute expressions in the Watch view (e.g. result=false, exception.printStackTrace() etc.).