The following would be nice to have:

:help name

(where name could be a qualified name)
which should print the html-ized doc comment for that item.
Most of the needed functionality should already be there in compiler/DocUtils.fr and compiler/EclipseUtils.fr
The only difficulty should be to keep track of the namespaces in scope according to the imports done by the user. This you need to resolve the name and get the corresponding symbol table entry, which could then be handed down to the documentation functions.

Also nice (but not really important) would be to have a command like

:java

to see the generated java code, maybe in an extra tab or page. I sometimes wanted this for answering "how would I write this Haskell code in Java" type questions on stackoverflow quickly. :)