Eclipse help won't show under Ubuntu

Question

Whenever I open some help within eclipse I get a page saying:

Server Error. The following error occurred: [code=CANT_CONNECT_LOOPBACK] Cannot connect

Answer 1

I know this is a late answer, but I had the same problem and resolved it, so to tie up this one...

This is a combination of two bugs:

(i) Eclipse's internal help browser doesn't use the Eclipse proxy settings! See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=318969

(and the bugs referenced in comment #7 therein)

(ii) Ubuntu's proxy support is horribly broken in certain subtle ways. See: https://bugs.launchpad.net/ubuntu/+bug/300271

The fix/workaround is to manually set the no_proxy environment variable before running eclipse (as reported in the Eclipse #308035 bug referenced from the 318969 one) e.g.

export no_proxy=127.0.0.1,localhost
eclipse &

Help then launches correctly within Eclipse. Of course, once Eclipse is launched (thus running its own internal HTTP server), you can also access the local help manually from another browser (or, if within the 'can't access 127.0.0.1' screen, there's an icon at the top to launch in an external window --> default system browser).

This may well apply on other Linux distros using Gnome.

[Couldn't post the 308035 bug link because my low reputation means I can only post 2 hyperlinks :-( Getting excited at this privilege come 10 reputation points :-)]