Thanks Mark, there is a 'Comment' command with no default binding and
'when'='editing java source' which I tried to assign ctrl-c ctrl-c
binding and which doesn't work, and then there is a 'toggle comment'
command with default binding ctrl-/, which i am able to change to ctrl-
c ctrl-c and it does work. Its a bit confusing. I'm new to eclipse,
and I use original emacs for c++.